fix(web): validate inputs in handleConfigSave to prevent fuzz bricking (M1)

Previously /config accepted any value and called ESP.restart() — fuzz tests (or any malicious POST) could save garbage SSIDs and brick the device until FTDI recovery. Now: - SSID: rejected if empty, >31 chars, non-printable, or all-same-char (HTTP 400) - Password: rejected if >63 chars - Hostname/city_name/ntp_server: length-validated - Numeric fields (timezone, brightness, intervals, lat/lon, display): clamped to safe ranges via constrain() Tested on hardware: ssid="AAAA..." now correctly returns HTTP 400 and preserves existing config. Device survives entire fuzz suite. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
fix(wifi): preserve AP_STA mode after WiFi.begin() kills the AP
2026-05-19 13:40:43 +01:00 · 2026-05-18 20:52:14 +01:00 · 2026-05-18 20:44:07 +01:00 · 2026-05-18 20:25:32 +01:00 · 2026-05-18 16:02:53 +01:00 · 2026-05-18 15:57:41 +01:00
22 changed files with 959 additions and 4602 deletions
@@ -25,3 +25,6 @@ build/
 # Secrets (in case someone accidentally commits credentials)
 secrets.h
 config_local.h
 # Internal backlogs (not for public repo)
 BACKLOG_*.md
@@ -5,15 +5,89 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 ## [1.9.7] - 2026-05-19
 ### Fixed
 - **Config endpoint accepted garbage values, bricking device** (M1): `/config` form handler
  now validates all inputs. SSID rejected if empty, >31 chars, non-printable, or all-same-char
  (fuzz garbage like "AAAA..."). Numeric fields are `constrain()`-ed to safe ranges
  (`ntp_interval`/`weather_interval`: 60–86400, `brightness`: 0–7, `timezone`: ±12h,
  `latitude`/`longitude`: physical ranges, `display_orientation`: 0–3). Invalid input
  returns HTTP 400 instead of silently saving and rebooting.
 ## [1.9.6] - 2026-05-18
 ### Fixed
 - **Weather hangs permanently after TCP timeout** (C1): `WEATHER_REQUESTING` state now has a
  15-second watchdog — if the HTTP callback never fires (NAT timeout, server half-close),
  state resets to IDLE and retry logic resumes
 - **All retry timers freeze at ~49 days** (C2): Replaced unsafe `millis() >= nextRetryTime`
  with subtraction-safe `(millis() - nextRetryTime) < 0x80000000UL` in RetryConfig and
  WiFiRetryConfig; fixed boot guard with static flag
 - **DST switches on wrong day** (H1): Last-Sunday formula was using year-only heuristic;
  now computes weekday of the 31st from current `tm_wday`: verified correct for 2026–2030
 - **Heap fragmentation from web API polling** (H2): Replaced String+= concatenation with
  `snprintf`+`sendContent` in `handleAPITime`, `handleAPIStatus`, `handleAPIDebug`,
  `handleAPIWeather` — eliminates permanent heap fragmentation from 1s JS polling
 - **Race condition on shared state** (H3): Added `volatile` to `weatherState` and `ntpState`
  — prevents compiler from caching stale values across ESPAsyncTCP callback boundaries
 - **Malformed JSON on long error messages**: `lastError` clamped to 79 chars before snprintf
 ### Changed
 - RAM usage: 37,268 bytes (46%) — down from 37,560 due to String elimination in API handlers
 ## [1.9.5] - 2026-05-18
 ### Fixed
 - **Temperature disappears permanently** (#9): After 3 consecutive API failures,
  the weather state machine was permanently locked — `weatherState` stayed `WEATHER_FAILED`
  and no new requests were ever made even after the API recovered. Fix: reset retry
  counter and state after max retries so periodic refresh resumes after next interval (30 min).
 ## [1.9.4] - 2026-05-14
 ### Fixed
 - **Date timezone** (#5): Date string now uses local time, so date rolls over at local midnight instead of UTC midnight
 - **Weather periodic refresh** (#7): Removed `WEATHER_SUCCESS` state that permanently blocked periodic weather updates after first fetch; also fixed "Last update" counter showing raw timestamp instead of elapsed seconds
 - **WiFi connects to wrong network** (#3): `WiFi.begin()` without params is now skipped when a saved SSID exists, preventing connection to SDK-cached open hotspots and config corruption
 ### Changed
 - WiFi startup: SDK-cached credentials only attempted on first boot (no saved SSID); subsequent boots go directly to saved credentials
 - ArduinoJson: `StaticJsonDocument` → `JsonDocument` for compatibility with ArduinoJson v7
 ### Removed
 - Unused `weekday` variable in NTP DST calculation (compiler warning)
 ### Internal
 - Split `clock_ntp_ota_v1.9/` directory renamed to `weather_clock/` — version no longer baked into path
 - Removed internal development documents from repository
 ## [1.9.3] - 2026-01-06
 ### Changed
 - Refactored monolithic 2,100-line `.ino` into modular structure:
  `display.cpp`, `ntp_client.cpp`, `weather.cpp`, `web_server.cpp`, `wifi_manager.cpp`
 ## [1.9.2] - 2026-01-06
 ### Fixed
 - **CRITICAL**: WiFi credentials no longer cleared on connection failure
  - Previous behavior erased SSID/password after failed connection attempts
  - Now credentials persist indefinitely through WiFi outages
 - OTA update credential loss issue (SDK credentials now tried first, then EEPROM)
 ### Added
 - **WiFi Resilience**: Infinite retry with exponential backoff (5s → 10s → 20s → ... → 5min max)
 - **Fallback AP**: "TJ56654-Setup" enabled after ~5 min of failed attempts
  - Device continues retry attempts while AP is active (dual STA+AP mode)
@@ -23,11 +97,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **SDK credentials support**: Tries WiFiManager-stored credentials first
 ### Changed
 - Clock continues running with last synced time during WiFi outages
 - Improved user experience during network failures
 - Removed aggressive credential clearing behavior
 ### Network Activity
 - NTP sync: 1 hour interval (pool.ntp.org:123 UDP)
 - Weather fetch: 30 min interval (api.open-meteo.com HTTP)
 - mDNS: continuous (224.0.0.251 UDP multicast)
@@ -36,22 +112,26 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [1.9.1] - 2026-01-03
 ### Fixed
 - **CRITICAL**: WiFi startup sequence - synchronous connection in setup() to ensure proper initialization order
 - Display blank screen for 10+ seconds on boot (now shows time after ~15 seconds)
 - "DNS resolution failed" errors during startup
 - Sunrise/sunset labels cut off on 128px screen (removed labels, arrows are self-explanatory)
 ### Changed
 - Hybrid WiFi model: synchronous in setup(), async reconnect in loop()
 - Display formatting: superscript degree symbol and lowercase 'c' for temperature
 - Sunrise/sunset screen now shows daylight duration (e.g., "Day 9h 41m") instead of static "Sun Times" text
 ### Documentation
 - Added detailed v1.9.1_HYBRID_FIX.md explaining startup sequence problem and solution
 ## [1.9.0] - 2026-01-02
 ### Added
 - Fully async architecture (zero blocking operations in loop)
 - Custom async NTP implementation (manual UDP packet handling)
 - Async HTTP weather fetch (AsyncHTTPRequest library)
@@ -59,12 +139,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Independent epoch tracking for accurate time between NTP syncs
 ### Changed
 - Replaced blocking NTPClient with custom async UDP implementation
 - Replaced blocking HTTP weather with AsyncHTTPRequest
 - Removed all delay() calls from loop()
 - WiFi connection now async (later fixed in v1.9.1)
 ### Performance
 - Loop time: 10ms → <1ms (10x improvement)
 - Weather fetch: 1-10s blocking → 0ms
 - NTP sync: 5-20s blocking → 0ms
@@ -72,6 +154,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - OTA updates now work during active weather fetching
 ### Technical
 - RAM usage: +536 bytes (36,980 → 37,516)
 - Flash usage: +1040 bytes (407,500 → 408,540)
 - IRAM: 61,987 bytes (94% - stable)
@@ -79,12 +162,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [1.8.0] - 2026-01-01
 ### Security
 - **CRITICAL**: Removed hardcoded WiFi credentials
 - Integrated WiFiManager for secure captive portal setup
 - Added config validation (magic number check)
 - Input sanitization to prevent buffer overflows
 ### Fixed
 - IRAM overflow crisis (94% → 70% via ICACHE_FLASH_ATTR)
 - NTP interval bug (config value was ignored, always used hardcoded 1 hour)
 - Boolean parsing errors in JSON config import/export
@@ -92,17 +177,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Memory leaks from String concatenation in web handlers
 ### Changed
 - Web responses now use chunked transfer (eliminated 140+ String concatenations)
 - Applied ICACHE_FLASH_ATTR to 26 functions (moved code from IRAM to Flash)
 - Improved error handling throughout codebase
 ### Performance
 - Peak heap usage reduced by ~8KB
 - EEPROM validation prevents loading corrupted config
 ## [1.7.0] - 2025-12-31
 ### Added
 - Initial working firmware with correct display support
 - NTP time synchronization
 - Weather data from Open-Meteo API (free, no API key required)
@@ -114,11 +202,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - EEPROM configuration persistence
 ### Hardware Discovery
 - Identified display as GM009605v4.3 (not TM1637 or TM1650)
 - Discovered swapped I2C pins: SDA=GPIO0, SCL=GPIO2
 - Switched to Adafruit_SSD1306 library
 ### Replaced
 - QWeather API → Open-Meteo (no registration required)
 - Proprietary firmware → Open source custom firmware
 - Insecure WiFi handling → WiFiManager with timeout
@@ -126,11 +216,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [1.6.0] - 2025-12-30 (unreleased)
 ### Attempted
 - TM1650 LED driver support (incorrect - device has OLED)
 ## [1.5.0] - 2025-12-29 (unreleased)
 ### Attempted
 - TM1637 7-segment display support (incorrect - device has OLED)
 ---
@@ -141,12 +233,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Minor version** (1.X.0): New features, backward-compatible
 - **Patch version** (1.9.X): Bug fixes, no new features
 ## Links
 - [Full v1.9 Release Notes](docs/v1.9_RELEASE_NOTES.md)
 - [v1.9.1 Hybrid Fix Details](docs/v1.9.1_HYBRID_FIX.md)
 - [v1.9.2 WiFi Resilience](docs/v1.9.2_WIFI_RESILIENCE.md)
 ---
-**Status**: v1.9.2 is production-ready and actively used 24/7.
+**Status**: v1.9.3 is production-ready and actively used 24/7.
@@ -7,6 +7,7 @@ Thank you for your interest in contributing! This project welcomes improvements,
 ### Reporting Bugs
 If you find a bug, please open an issue with:
 - Clear description of the problem
 - Steps to reproduce
 - Expected vs actual behavior
@@ -16,6 +17,7 @@ If you find a bug, please open an issue with:
 ### Suggesting Features
 Feature requests are welcome! Please include:
 - Use case description
 - Why this would be useful
 - Any implementation ideas
@@ -38,16 +40,19 @@ Feature requests are welcome! Please include:
 ### Code Guidelines
 **Memory Safety:**
 - Check IRAM usage after adding code
 - Use fixed-size buffers instead of dynamic allocation where possible
 - Prefer `snprintf` over String concatenation
 **Async Architecture:**
 - Keep loop() non-blocking (no delay() calls)
 - Use state machines for multi-step operations
 - Add exponential backoff to network operations
 **Testing:**
 - Test on ESP-01S hardware (1MB flash, 80KB RAM)
 - Verify OTA updates work
 - Check 24h stability
@@ -55,18 +60,21 @@ Feature requests are welcome! Please include:
 ## Development Setup
 ### Requirements
 - Arduino IDE 1.8.x or 2.x
 - ESP8266 board support (v3.0.0+)
 - Libraries (see README)
 ### Building
 ```bash
 # Arduino IDE: Sketch → Verify/Compile
 # Or use arduino-cli:
-arduino-cli compile --fqbn esp8266:esp8266:generic src/clock_ntp_ota_v1.9.ino
+arduino-cli compile --fqbn esp8266:esp8266:generic firmware/weather_clock
 ```
 ### Testing
 ```bash
 # Upload via FTDI (first time)
 arduino-cli upload -p /dev/cu.usbserial* --fqbn esp8266:esp8266:generic
@@ -79,7 +87,7 @@ curl -u admin:admin -F "file=@build/*.bin" http://192.168.x.x/update
 ```
 esp8266-weather-clock-opensource/
-├── src/                    # Main firmware source
+├── firmware/               # Main firmware source (weather_clock/)
 ├── docs/                   # Documentation
 ├── images/                 # Photos and screenshots
 ├── README.md               # Main documentation
@@ -1,800 +0,0 @@
 # ESP8266 Weather Clock - Full Project Context
 **Last Updated**: 2026-01-03
 **Current Version**: v1.9.1 (Production Ready)
 **GitHub**: https://github.com/petrochen/esp8266-weather-clock-opensource
 ---
 ## Table of Contents
 1. [Project Overview](#project-overview)
 2. [Hardware Details](#hardware-details)
 3. [Development History](#development-history)
 4. [Current Status (v1.9.1)](#current-status-v191)
 5. [Technical Architecture](#technical-architecture)
 6. [Security Issues Fixed](#security-issues-fixed)
 7. [Files & Structure](#files--structure)
 8. [Git Repository](#git-repository)
 9. [Next Steps](#next-steps)
 10. [Key Learnings](#key-learnings)
 ---
 ## Project Overview
 ### What Is This?
 Complete reverse engineering and firmware replacement for an ESP8266-based weather clock purchased from AliExpress (model TJ-56-654, €5).
 ### Why?
 **Original firmware had critical security vulnerabilities:**
 - WiFi password displayed in plaintext
 - Persistent open access point running in parallel to home WiFi
 - Dependency on Chinese cloud service (QWeather) requiring API key registration
 - No OTA updates (required physical FTDI access for updates)
 **Solution:** Complete custom firmware with security, performance, and features.
 ### Key Features
 - ✅ **Security**: No password leaks, WiFiManager captive portal, no hardcoded credentials
 - ✅ **Performance**: Fully async architecture, <1ms loop time (was 10ms+)
 - ✅ **Weather**: Open-Meteo API (free, no registration, no API key)
 - ✅ **Updates**: OTA via web interface + ArduinoOTA
 - ✅ **Interface**: Web UI, REST API, full configuration
 - ✅ **Display**: 3 rotating modes (time, weather, sunrise/sunset with daylight duration)
 - ✅ **Time**: NTP sync with timezone + automatic European DST
 ---
 ## Hardware Details
 ### Device Purchased
 - **Product**: ESP8266 Mini Weather Clock Kit
 - **Model**: TJ-56-654
 - **Source**: [AliExpress Link](https://pt.aliexpress.com/item/1005008333782531.html)
 - **Price**: €5 EUR (~$5.50 USD)
 - **Size**: 40mm x 40mm x 43mm (transparent acrylic case)
 ### Components
 #### ESP-01S WiFi Module
 - **Chip**: ESP8266EX
 - **Flash**: 1MB (8Mbit)
 - **RAM**: 80KB total
 - **CPU**: 80MHz
 - **WiFi**: 802.11 b/g/n (2.4GHz only)
 - **GPIO**: Only GPIO0 and GPIO2 available
 - **Voltage**: 3.3V ⚠️ NOT 5V tolerant
 #### Display Module
 - **Model**: GM009605v4.3
 - **Type**: OLED (128x64 pixels, 0.96 inches)
 - **Controller**: SSD1306/SH1106 compatible
 - **Interface**: I2C
 - **I2C Address**: 0x3C (default), 0x3D (fallback)
 - **Colors**: Monochrome (white on black)
 #### Pin Mapping (CRITICAL!)
 **Non-standard I2C mapping:**
 - SDA: GPIO0 (not GPIO4 as typical)
 - SCL: GPIO2 (not GPIO5 as typical)
 This mapping is **backwards** from standard ESP8266 breakout boards!
 ```cpp
 Wire.begin(0, 2);  // SDA=GPIO0, SCL=GPIO2
 ```
 ### Power Supply
 - Input: 5V via Micro-USB
 - Current: 80-120mA typical
 - Regulator: Onboard 3.3V LDO
 ---
 ## Development History
 ### Timeline
 **2025-12-29**: v1.5 (unreleased)
 - Attempted TM1637 7-segment display support
 - ❌ Wrong - device has OLED, not 7-segment LEDs
 **2025-12-30**: v1.6 (unreleased)
 - Attempted TM1650 LED driver support
 - ❌ Wrong - I2C addresses didn't match
 **2025-12-31**: v1.7 ✅
 - ✅ Identified correct display: GM009605v4.3 (SSD1306-compatible OLED)
 - ✅ Discovered swapped pins: SDA=GPIO0, SCL=GPIO2
 - ✅ Switched to Adafruit_SSD1306 library
 - ✅ Basic time display working
 - ✅ WiFiManager integration
 - ✅ First OTA deployment
 **2026-01-01**: v1.8 🔒
 - 🔒 **Security fixes**:
  - Removed hardcoded WiFi credentials
  - Added config validation (magic number check)
  - Input sanitization (buffer overflow protection)
 - 🛠️ **Stability fixes**:
  - IRAM crisis fix (94% → 70% via ICACHE_FLASH_ATTR on 26 functions)
  - NTP interval bug (config value was ignored)
  - Boolean parsing errors in JSON import/export
  - Infinite loop protection in display rotation
 - ⚡ **Performance**:
  - Chunked HTTP responses (eliminated 140+ String concatenations)
  - Peak heap usage reduced by ~8KB
  - Memory leaks fixed
 **2026-01-02**: v1.9.0 ⚡
 - ⚡ **Full async refactoring**:
  - Async HTTP weather fetch (AsyncHTTPRequest library)
  - Custom async NTP implementation (manual UDP packets)
  - Async WiFi connection (state machine)
  - Removed all delay() calls from loop()
  - Exponential backoff retry logic
 - 📊 **Performance results**:
  - Loop time: 10ms → <1ms (10x improvement)
  - Weather fetch: 1-10s blocking → 0ms
  - NTP sync: 5-20s blocking → 0ms
  - WiFi reconnect: 15s blocking → 0ms
 - ❌ **Problem discovered**:
  - Display blank for 10+ seconds on boot
  - "DNS resolution failed" errors
 **2026-01-03**: v1.9.1 (Current) 🎯
 - 🔧 **Critical fix**: Hybrid WiFi model
  - Synchronous WiFi in setup() (waits up to 10 seconds)
  - Async WiFi reconnect in loop() (non-blocking)
  - Ensures proper initialization order: WiFi → OTA → web → NTP
 - 📺 **Display improvements**:
  - Fixed sunrise/sunset labels cutoff (removed labels, kept arrows)
  - Superscript degree symbol (°c)
  - Daylight duration display instead of static "Sun Times"
 - ✅ **Result**: Production ready, tested 24/7
 ---
 ## Current Status (v1.9.1)
 ### Version Information
 **Firmware**: v1.9.1 (Production Ready)
 **Released**: 2026-01-03
 **Status**: Actively running 24/7, stable
 ### Memory Usage
 | Resource | Used | Total | Usage | Status |
 |----------|------|-------|-------|--------|
 | Flash | 408,844 | 1,048,576 | 38% | ✅ Plenty |
 | RAM | 37,644 | 80,192 | 46% | ✅ Safe |
 | IRAM | 61,987 | 65,536 | 94% | ⚠️ Critical but stable |
 **IRAM Note**: 94% is acceptable because:
 - ICACHE_FLASH_ATTR applied to 26 functions
 - Stable across v1.8 → v1.9.1
 - No growth observed in testing
 ### Performance Metrics
 - **Loop time**: <1ms (was 10ms+ before async)
 - **Boot to time display**: ~15 seconds
 - **WiFi connection**: 5-10 seconds (synchronous in setup)
 - **NTP sync interval**: Configurable (default 1 hour)
 - **Weather update interval**: Configurable (default 30 minutes)
 ### Uptime
 - ✅ 24+ hours stable
 - ✅ No memory leaks
 - ✅ No crashes or reboots
 - ✅ OTA updates work during operation
 ---
 ## Technical Architecture
 ### Async State Machines
 #### Weather State Machine
 ```cpp
 enum WeatherState { IDLE, REQUESTING, SUCCESS, FAILED };
 ```
 - Library: AsyncHTTPRequest_Generic v1.13.0
 - API: Open-Meteo (free, no API key)
 - Callback: `onWeatherResponse()`
 - Retry: Exponential backoff (1s → 2s → 4s, max 3 retries)
 #### NTP State Machine
 ```cpp
 enum NTPState { IDLE, REQUEST_SENT, WAITING, SUCCESS, FAILED };
 ```
 - Custom manual UDP packet building/parsing
 - Independent epoch tracking: `syncedEpoch`, `syncedMillis`, `timeIsSynced`
 - Non-blocking UDP checks via `parsePacket()`
 - Timeout: 5 seconds
 - Why manual? NTPClient library is inherently blocking
 #### WiFi State Machine
 ```cpp
 enum WiFiConnectionState { IDLE, CONNECTING, CONNECTED, FAILED };
 ```
 **Hybrid model** (critical for v1.9.1):
 - **Setup phase**: Synchronous (waits up to 10 seconds)
  - Why? OTA, web server, NTP all need WiFi ready
  - Prevents "DNS resolution failed" errors
  - Ensures time appears on display immediately after WiFi connects
 - **Loop phase**: Asynchronous (checks every 5 seconds)
  - Why? Don't freeze device if WiFi drops during operation
  - Graceful reconnection without user impact
 ### Configuration Storage
 **EEPROM struct (512 bytes, 26 fields):**
 ```cpp
 struct Config {
  char ssid[32];                      // WiFi network name
  char password[64];                  // WiFi password
  int timezone_offset;                // Seconds from UTC
  bool dst_enabled;                   // Auto DST (European rules)
  uint8_t brightness;                 // Display brightness (0-7)
  char ntp_server[64];                // NTP server address
  unsigned long ntp_interval;         // NTP sync interval (seconds)
  bool hour_format_24;                // 24h vs 12h display
  char hostname[32];                  // mDNS hostname
  float latitude;                     // Weather location
  float longitude;                    // Weather location
  char city_name[32];                 // Display in weather mode
  bool weather_enabled;               // Feature toggle
  unsigned long weather_interval;     // Update interval (seconds)
  unsigned long display_rotation_sec; // Mode switch interval
  bool show_weather;                  // Enable weather mode
  bool show_sunrise_sunset;           // Enable sunrise/sunset mode
  uint8_t display_orientation;        // Screen rotation (0-3)
  uint32_t magic;                     // 0xC10CC10C - validation
 };
 ```
 **Validation**: Magic number check prevents loading corrupted EEPROM data.
 ### Display Modes
 **Mode 1: Time Mode**
 - Large HH:MM display
 - Blinking colon (500ms interval)
 - Day of week + date
 - 24/12 hour format support
 **Mode 2: Weather Mode**
 - Temperature with superscript °c
 - City name at bottom
 - Example: "15.4°c" + "Portimao"
 **Mode 3: Sunrise/Sunset Mode**
 - Sunrise time with ↑ arrow
 - Sunset time with ↓ arrow
 - Daylight duration (e.g., "Day 9h 41m")
 - Calculation: sunset - sunrise = total daylight minutes
 **Rotation**: Configurable interval (default 5 seconds), gracefully skips disabled modes.
 ### Memory Optimization Techniques
 **1. ICACHE_FLASH_ATTR**
 Applied to 26 functions to move code from IRAM to Flash:
 - All web handlers (15 functions)
 - Setup functions (5 functions)
 - Utilities (6 functions)
 Result: IRAM usage manageable at 94%
 **2. Chunked HTTP Responses**
 ```cpp
 // ❌ BAD - 140+ concatenations
 String html = "";
 html += F("<!DOCTYPE html>");
 html += F("<head>...");
 // ✅ GOOD - Chunked transfer
 server.setContentLength(CONTENT_LENGTH_UNKNOWN);
 server.send(200, "text/html", "");
 server.sendContent_P(HTML_HEADER);
 server.sendContent_P(HTML_FOOTER);
 server.sendContent("");
 ```
 Result: ~8KB peak heap reduction
 **3. Fixed-Size Buffers**
 No dynamic String allocations in loops:
 ```cpp
 char buf[150];
 snprintf_P(buf, sizeof(buf), PSTR("<div>IP: %s</div>"),
          WiFi.localIP().toString().c_str());
 ```
 ---
 ## Security Issues Fixed
 ### Original Firmware Vulnerabilities
 **1. WiFi Password Leak (CRITICAL)**
 - Open access point remained active after setup
 - Web interface displayed WiFi password in plaintext
 - Anyone within range could connect and read password
 - **Impact**: Full network compromise
 **2. Cloud Dependency**
 - Required QWeather API (Chinese service)
 - Needed account registration + API key
 - Unknown data collection practices
 - **Impact**: Privacy concerns, vendor lock-in
 **3. No OTA Updates**
 - Required physical FTDI connection for updates
 - Difficult for non-technical users
 - **Impact**: Security vulnerabilities can't be patched remotely
 **4. Hardcoded Credentials**
 - Default WiFi credentials in source code
 - No secure setup flow
 - **Impact**: Easy attack vector
 ### Custom Firmware Solutions
 **1. WiFiManager Integration ✅**
 - Captive portal for secure first-time setup
 - AP automatically closes after 180 seconds
 - Fallback AP only on connection failure
 - Password-protected fallback (customizable)
 **2. Open-Meteo API ✅**
 - Free weather service
 - No registration required
 - No API key needed
 - European service (GDPR compliant)
 **3. OTA Updates ✅**
 - Web-based upload at `/update`
 - ArduinoOTA for IDE uploads
 - Password-protected (admin/admin - customizable)
 - Non-blocking during operation
 **4. No Hardcoded Secrets ✅**
 - All credentials stored in EEPROM
 - Magic number validation
 - Factory reset capability
 - Configuration import/export
 ---
 ## Files & Structure
 ### Project Directory
 **Location**: `/Users/apetrochenko/Library/Mobile Documents/com~apple~CloudDocs/src/arduino/clock/esp8266-weather-clock-opensource`
 ### Key Files
 **Root Level:**
 - `README.md` (26KB) - Main documentation (blog-style)
 - `LICENSE` - MIT License
 - `CHANGELOG.md` - Version history
 - `CONTRIBUTING.md` - Contribution guidelines
 - `PROJECT_STRUCTURE.md` - Directory layout
 - `PROJECT_CONTEXT.md` - This file
 - `PUBLISH_TO_GITHUB.md` - GitHub publishing guide
 - `.gitignore` - Git exclusions
 **Source Code:**
 - `src/clock_ntp_ota_v1.9.ino` (65KB, 2,096 lines)
 **Documentation:**
 - `docs/INSTALLATION.md` (18KB) - Complete installation guide
 - `docs/HARDWARE.md` (8KB) - Hardware specs + pinout
 - `docs/v1.9_RELEASE_NOTES.md` (7KB) - v1.9.0 changelog
 - `docs/v1.9.1_HYBRID_FIX.md` (6KB, Russian) - v1.9.1 fix explanation
 **Images:**
 - `images/product/` - 6 AliExpress product photos
  - 01-main-product.webp
  - 02-components.webp
  - 03-weather-forecast.webp
  - 04-temperature-display.webp
  - 05-details.webp
  - 06-size.webp
 - `images/build/` - 3 display screenshots
  - display-time.png
  - display-temperature.png
  - display-sunrise-sunset.png
 **GitHub Config:**
 - `.github/workflows/build.yml` - CI/CD pipeline
 - `.github/ISSUE_TEMPLATE/bug_report.md`
 - `.github/ISSUE_TEMPLATE/feature_request.md`
 ### Compiled Artifacts (not in git)
 ```
 build/
 ├── clock_ntp_ota_v1.9.ino.bin  (409KB) - Flash this via OTA
 ├── clock_ntp_ota_v1.9.ino.elf  - Debug symbols
 └── clock_ntp_ota_v1.9.ino.map  - Memory map
 ```
 ---
 ## Git Repository
 ### GitHub Details
 - **Repository**: https://github.com/petrochen/esp8266-weather-clock-opensource
 - **Owner**: petrochen (Andrey Petrochenko)
 - **Visibility**: Public
 - **License**: MIT
 - **Created**: 2026-01-03
 ### Repository Configuration
 **Enabled Features:**
 - ✅ Issues
 - ✅ Discussions
 - ✅ GitHub Actions (CI/CD)
 - ✅ Releases
 **Topics (Tags):**
 - `esp8266`, `arduino`, `iot`, `weather-station`
 - `reverse-engineering`, `security`, `oled-display`
 - `ntp`, `ota-updates`, `open-meteo`
 **Badges:**
 - Release version (auto-updates)
 - License (MIT)
 - Build status (CI/CD)
 - Open issues count
 - Hardware (ESP-01S)
 - Status (Production Ready)
 ### Current Release
 **Tag**: v1.9.1
 **URL**: https://github.com/petrochen/esp8266-weather-clock-opensource/releases/tag/v1.9.1
 **Status**: Production Ready
 **Created**: 2026-01-03
 ### Git Commits
 **Total**: 3 commits
 1. `8f0df02` - Initial commit: v1.9.1 production firmware
 2. `f2dc2fb` - Add dynamic GitHub badges to README
 3. `2205445` - Update price: $12 → €5
 ### Web Interface URLs
 - **Main**: https://github.com/petrochen/esp8266-weather-clock-opensource
 - **Issues**: https://github.com/petrochen/esp8266-weather-clock-opensource/issues
 - **Discussions**: https://github.com/petrochen/esp8266-weather-clock-opensource/discussions
 - **Actions**: https://github.com/petrochen/esp8266-weather-clock-opensource/actions
 - **Releases**: https://github.com/petrochen/esp8266-weather-clock-opensource/releases
 ---
 ## Next Steps
 ### Planned Features (v1.10 or v2.0)
 **1. Home Assistant Integration (High Priority)**
 User specifically wants custom display screens pulling data from Home Assistant.
 **Implementation ideas:**
 - Add REST API client to fetch HA sensor data
 - New display modes:
  - Energy usage dashboard
  - Room temperatures (multiple sensors)
  - Air quality / CO2 levels
  - Automation states (alarm, doors, lights)
 - Configuration: HA server URL, access token, entity IDs
 - Update interval: configurable (default 30 seconds)
 **Technical approach:**
 - Use AsyncHTTPRequest for non-blocking HA API calls
 - JSON parsing with ArduinoJson library
 - Store HA config in EEPROM (new fields)
 - New web UI section for HA configuration
 **2. MQTT Support**
 - Publish time/weather data to MQTT broker
 - Subscribe to topics for display content
 - Enable automation triggers
 - Library: PubSubClient (async wrapper needed)
 **3. WebSocket Live Updates**
 - Replace polling with WebSocket
 - Real-time config changes
 - Live display preview in web UI
 - Push notifications for updates
 **4. Multiple Weather Locations**
 - Store 2-3 favorite locations
 - Rotate between them
 - Useful for travelers or multiple homes
 **5. Display Animations**
 - Smooth transitions between modes
 - Weather icons (sunny, cloudy, rainy)
 - Sunrise/sunset animations
 ### Code Quality Improvements
 **1. Modular Architecture (v2.0)**
 Split monolith (2,096 lines) into modules:
 ```
 src/
 ├── main.ino
 ├── config.h
 ├── display.cpp/h
 ├── network.cpp/h
 ├── weather.cpp/h
 ├── webserver.cpp/h
 └── home_assistant.cpp/h  (new)
 ```
 **2. ArduinoJson Integration**
 Replace manual JSON parsing (173 lines) with library:
 - Cleaner code
 - Better error handling
 - Type safety
 **3. Constants Organization**
 Eliminate magic numbers:
 ```cpp
 namespace Hardware {
  constexpr uint8_t I2C_SDA_PIN = 0;
  constexpr uint8_t I2C_SCL_PIN = 2;
 }
 ```
 **4. Unit Tests**
 - Test state machines
 - Test JSON parsing
 - Test time calculations
 - Mock network calls
 ### Documentation Improvements
 **1. Video Tutorial**
 - YouTube walkthrough
 - FTDI connection demo
 - OTA update demo
 - Web configuration walkthrough
 **2. Troubleshooting Flow Chart**
 Visual guide for common issues:
 - Display not working
 - WiFi not connecting
 - Time not syncing
 - Weather not updating
 **3. Localization**
 Translate docs to:
 - Russian (v1.9.1_HYBRID_FIX.md already in Russian)
 - Spanish
 - Portuguese
 **4. Home Assistant Integration Guide**
 Complete guide when HA support is added.
 ### Community Engagement
 **1. Reddit Posts**
 Subreddits to share on:
 - r/esp8266
 - r/arduino
 - r/selfhosted
 - r/homeassistant (after HA integration)
 - r/ReverseEngineering
 **2. Hackaday**
 Submit project tip: https://hackaday.com/submit-a-tip/
 **3. Hackster.io**
 Create full project page with build guide.
 **4. Awesome Lists**
 Add to "awesome ESP8266" and "awesome IoT" lists.
 ---
 ## Key Learnings
 ### Hardware
 1. **Always verify pinouts** - Don't assume standard mappings
 2. **FTDI is essential** - $2 adapter unlocks any ESP8266 device
 3. **Read PCB markings** - Model numbers save hours of guessing
 4. **Test voltage** - ESP8266 is NOT 5V tolerant
 5. **Document discoveries** - Pin mappings, I2C addresses, display models
 ### Software
 1. **Async is hard but worth it** - Fully non-blocking eliminates freezes
 2. **IRAM is precious** - Use ICACHE_FLASH_ATTR liberally on ESP8266
 3. **Hybrid approaches work** - Don't be dogmatic (sync WiFi in setup() was correct)
 4. **State machines scale** - Better than callback hell for complex async
 5. **Test on real hardware** - Emulators miss pin issues and memory constraints
 ### Security
 1. **IoT security is often terrible** - Always audit before trusting
 2. **Open source is safer** - Closed firmware is a black box
 3. **Defaults matter** - Insecure defaults (open AP, plaintext passwords) are vulnerabilities
 4. **Defense in depth** - Multiple layers catch mistakes
 5. **Update mechanism is critical** - OTA enables security patches
 ### Development
 1. **OTA from day 1** - FTDI flashing gets old fast
 2. **Version control** - Backups (.bak, .bak2) saved the project multiple times
 3. **Document as you go** - Release notes prevent "what was I thinking?" moments
 4. **Incremental improvements** - v1.7 → v1.8 → v1.9.x made debugging manageable
 5. **User testing** - Photos from user revealed display cutoff issues
 ### Project Management
 1. **Understand user needs** - User wanted Home Assistant integration (plan for it)
 2. **Security first** - Privacy/security was main motivation
 3. **Performance matters** - 10ms loop → <1ms dramatically improves UX
 4. **Documentation is product** - Good docs = more users = more contributors
 5. **Publish early** - GitHub repo enables community contributions
 ---
 ## Quick Reference
 ### Current Device Configuration
 **Hardware:**
 - Device: TJ-56-654 Weather Clock
 - Location: User's home network
 - IP: 192.168.2.47
 - Hostname: tj56654-clock.local
 **Software:**
 - Firmware: v1.9.1
 - WiFi: SibWings
 - Weather: Portimao, Portugal (37.19°N, 8.54°W)
 - Timezone: UTC+0 (Lisbon) with auto DST
 - NTP: pool.ntp.org (1 hour interval)
 **Access:**
 - Web UI: http://192.168.2.47 or http://tj56654-clock.local
 - OTA Update: http://192.168.2.47/update (admin/admin)
 - API Base: http://192.168.2.47/api/
 ### Important Commands
 **Compile:**
 ```bash
 arduino-cli compile --fqbn esp8266:esp8266:generic \
  src/clock_ntp_ota_v1.9.ino
 ```
 **Upload OTA:**
 ```bash
 curl -u admin:admin \
  -F "file=@build/clock_ntp_ota_v1.9.ino.bin" \
  http://192.168.2.47/update
 ```
 **Check status:**
 ```bash
 curl http://192.168.2.47/api/status | jq
 ```
 **View logs:**
 ```bash
 # Connect via serial (if FTDI attached)
 screen /dev/cu.usbserial* 115200
 ```
 ### Library Dependencies
 Required libraries (install via Arduino Library Manager):
 | Library | Version | Purpose |
 |---------|---------|---------|
 | Adafruit GFX Library | 1.11.0+ | Graphics primitives |
 | Adafruit SSD1306 | 2.5.0+ | OLED display driver |
 | NTPClient | 3.2.0+ | NTP time sync (base) |
 | WiFiManager | 2.0.0+ | Captive portal |
 | AsyncHTTPRequest_Generic | 1.13.0+ | Async weather fetch |
 | ESPAsyncTCP | 1.2.2+ | Async TCP layer |
 ### External APIs
 **Open-Meteo:**
 - URL: https://api.open-meteo.com/v1/forecast
 - Authentication: None (free, no API key)
 - Rate limit: None (reasonable use)
 - Documentation: https://open-meteo.com/en/docs
 **NTP:**
 - Default: pool.ntp.org
 - Protocol: UDP port 123
 - Fallbacks: time.google.com, time.cloudflare.com
 ---
 ## Contact & Collaboration
 **GitHub**: https://github.com/petrochen/esp8266-weather-clock-opensource
 **Issues**: https://github.com/petrochen/esp8266-weather-clock-opensource/issues
 **Discussions**: https://github.com/petrochen/esp8266-weather-clock-opensource/discussions
 **Contributions welcome!** See [CONTRIBUTING.md](CONTRIBUTING.md)
 ---
 ## Summary
 This project successfully transformed a €5 AliExpress IoT device with critical security vulnerabilities into a fully secure, high-performance, feature-rich smart clock with open-source firmware.
 **Key achievements:**
 - ✅ Eliminated WiFi password leak vulnerability
 - ✅ Achieved <1ms loop time (10x performance improvement)
 - ✅ Enabled OTA updates (no more FTDI wiring)
 - ✅ Free weather API (no registration)
 - ✅ Full async architecture (zero blocking)
 - ✅ Production-ready stability (24/7 uptime)
 - ✅ Open-source on GitHub (MIT license)
 - ✅ Comprehensive documentation (100KB+ docs)
 **Next milestone**: Home Assistant integration for custom display screens.
 **Status**: Project complete and ready for community contributions! 🚀
 ---
 **Last session work (2026-01-03):**
 1. ✅ Compiled v1.9.1 with daylight duration feature
 2. ✅ Uploaded via OTA to device (192.168.2.47)
 3. ✅ Created complete GitHub repository structure
 4. ✅ Published to https://github.com/petrochen/esp8266-weather-clock-opensource
 5. ✅ Created release v1.9.1
 6. ✅ Added badges, topics, documentation
 7. ✅ Fixed price ($12 → €5)
 8. ✅ Saved full project context
 **Repository ready for sharing on Reddit, Hackaday, and other communities!**
@@ -1,249 +0,0 @@
 # Project Structure
 This document describes the organization of the ESP8266 Weather Clock firmware repository.
 ## Directory Layout
 ```
 esp8266-weather-clock-opensource/
 │
 ├── README.md                      # Main documentation (start here!)
 ├── LICENSE                        # MIT License
 ├── CHANGELOG.md                   # Version history
 ├── CONTRIBUTING.md                # Contribution guidelines
 ├── PROJECT_STRUCTURE.md           # This file
 ├── .gitignore                     # Git exclusions
 │
 ├── src/                           # Source code
 │   └── clock_ntp_ota_v1.9.ino     # Main firmware (2,096 lines)
 │
 ├── docs/                          # Documentation
 │   ├── INSTALLATION.md            # Complete installation guide
 │   ├── HARDWARE.md                # Hardware specs and pinout
 │   ├── v1.9_RELEASE_NOTES.md      # v1.9.0 release notes
 │   └── v1.9.1_HYBRID_FIX.md       # v1.9.1 WiFi startup fix
 │
 ├── images/                        # Photos and screenshots
 │   ├── product/                   # AliExpress product photos
 │   │   ├── 01-main-product.webp   # Main product shot
 │   │   ├── 02-components.webp     # Kit components
 │   │   ├── 03-weather-forecast.webp
 │   │   ├── 04-temperature-display.webp
 │   │   ├── 05-details.webp        # Transparent case details
 │   │   └── 06-size.webp           # Dimensions (40x40x43mm)
 │   │
 │   └── build/                     # Custom firmware screenshots
 │       ├── display-time.png       # Time display mode
 │       ├── display-temperature.png # Weather display mode
 │       └── display-sunrise-sunset.png # Solar display mode
 │
 └── .github/                       # GitHub-specific files
    ├── workflows/
    │   └── build.yml              # CI: Auto-build on push
    │
    └── ISSUE_TEMPLATE/
        ├── bug_report.md          # Bug report template
        └── feature_request.md     # Feature request template
 ```
 ## Key Files
 ### Root Level
 **README.md** (11KB)
 - Main project documentation
 - Blog-style narrative about reverse engineering
 - Security issues discovered
 - Complete feature list
 - Installation quickstart
 - API documentation
 **LICENSE** (MIT)
 - Permissive open source license
 - Use freely, modify, distribute
 **CHANGELOG.md**
 - Version history: v1.5 → v1.9.1
 - Features, fixes, breaking changes
 - Migration notes
 **CONTRIBUTING.md**
 - How to contribute
 - Code style guidelines
 - Testing requirements
 ### Source Code (`/src`)
 **clock_ntp_ota_v1.9.ino**
 - Main firmware file (2,096 lines)
 - ESP8266 Arduino sketch
 - Requires libraries:
  - Adafruit GFX & SSD1306
  - NTPClient
  - WiFiManager
  - AsyncHTTPRequest_Generic
  - ESPAsyncTCP
 **Architecture:**
 - Fully async (zero blocking in loop)
 - State machines: WiFi, NTP, Weather
 - Hybrid model: sync WiFi in setup(), async in loop()
 - Memory-optimized: ICACHE_FLASH_ATTR on 26 functions
 **Configuration:**
 - 26-field struct stored in EEPROM
 - Magic number validation
 - Web-based config UI
 ### Documentation (`/docs`)
 **INSTALLATION.md** (18KB)
 - Complete step-by-step installation guide
 - Arduino IDE setup
 - FTDI wiring diagrams
 - OTA update instructions
 - Comprehensive troubleshooting
 **HARDWARE.md** (8KB)
 - ESP-01S specifications
 - Pin mapping (SDA=GPIO0, SCL=GPIO2)
 - Display module details (GM009605v4.3)
 - Power requirements
 - Memory layout
 - Safety warnings
 **v1.9_RELEASE_NOTES.md** (7KB)
 - Detailed v1.9.0 changelog
 - Performance improvements
 - Async architecture explanation
 - Memory usage comparison
 - Testing checklist
 **v1.9.1_HYBRID_FIX.md** (Russian, 6KB)
 - Critical startup fix documentation
 - WiFi synchronous vs async tradeoffs
 - Timeline diagrams
 - Before/after comparison
 ### Images (`/images`)
 **Product Photos** (`/product`)
 - Original AliExpress product images
 - DIY kit components
 - Transparent acrylic case
 - Size reference (40mm cube)
 **Build Photos** (`/build`)
 - Custom firmware screenshots
 - Three display modes:
  1. Time mode (10:34 + date)
  2. Weather mode (15.4°c + city)
  3. Sunrise/sunset mode (times + daylight duration)
 ### GitHub Config (`/.github`)
 **Workflows**
 - `build.yml`: CI pipeline
  - Auto-compile on push
  - Check firmware size < 470KB
  - Upload build artifacts
  - Attach binaries to releases
 **Issue Templates**
 - `bug_report.md`: Structured bug reports
 - `feature_request.md`: Feature suggestions
 ## Build Artifacts (ignored by git)
 When you compile locally, these are created:
 ```
 build/
 ├── clock_ntp_ota_v1.9.ino.bin     # Flash this via OTA
 ├── clock_ntp_ota_v1.9.ino.elf     # Debug symbols
 └── clock_ntp_ota_v1.9.ino.map     # Memory map
 ```
 **Note**: `build/` is in `.gitignore` - artifacts not committed to repo.
 ## File Sizes
 | File | Size | Description |
 |------|------|-------------|
 | `src/*.ino` | 65KB | Main source code |
 | `build/*.bin` | 409KB | Compiled firmware |
 | `README.md` | 45KB | Main docs |
 | `docs/INSTALLATION.md` | 18KB | Install guide |
 | `docs/HARDWARE.md` | 8KB | Hardware specs |
 ## Memory Usage
 **Compiled firmware (v1.9.1):**
 - Flash: 408,844 / 1,048,576 bytes (38%)
 - RAM: 37,644 / 80,192 bytes (46%)
 - IRAM: 61,987 / 65,536 bytes (94%) ⚠️
 **Why 94% IRAM is acceptable:**
 - ICACHE_FLASH_ATTR applied to all web handlers
 - Stable across versions v1.8-v1.9.1
 - No IRAM growth observed in testing
 ## Version Control
 **Branches:**
 - `main`: Stable releases (v1.9.1)
 - `develop`: Work-in-progress features
 - `feature/*`: New feature branches
 **Tags:**
 - `v1.9.1`: Current production release
 - `v1.9.0`: Async refactoring
 - `v1.8.0`: Security + stability fixes
 - `v1.7.0`: Initial working firmware
 ## Not Included (Why)
 **What's NOT in this repo:**
 - Build artifacts (`.bin`, `.elf`, `.map`) - generated locally
 - Backup files (`.bak`, `.bak2`) - development artifacts
 - IDE configs (`.vscode/`, `.idea/`) - personal preferences
 - macOS metadata (`.DS_Store`) - system files
 - Secrets (`config_local.h`) - would leak credentials
 These are excluded via `.gitignore`.
 ## How to Navigate
 **For users:**
 1. Start with `README.md` (overview + quickstart)
 2. Follow `docs/INSTALLATION.md` (step-by-step setup)
 3. Check `CHANGELOG.md` (version history)
 **For developers:**
 1. Read `CONTRIBUTING.md` (guidelines)
 2. Study `src/clock_ntp_ota_v1.9.ino` (source code)
 3. Review `docs/HARDWARE.md` (hardware constraints)
 4. Check `.github/workflows/build.yml` (CI setup)
 **For hardware hackers:**
 1. Check `docs/HARDWARE.md` (pinout, specs)
 2. View `images/product/` (original device photos)
 3. Read `README.md` section "Hardware Discovery"
 **For troubleshooters:**
 1. Open `docs/INSTALLATION.md`
 2. Jump to "Troubleshooting" section
 3. Check `images/build/` for reference screenshots
 ## Quick Links
 - **Main docs**: [README.md](README.md)
 - **Install guide**: [docs/INSTALLATION.md](docs/INSTALLATION.md)
 - **Hardware specs**: [docs/HARDWARE.md](docs/HARDWARE.md)
 - **Changelog**: [CHANGELOG.md](CHANGELOG.md)
 - **Contributing**: [CONTRIBUTING.md](CONTRIBUTING.md)
 ---
 **Last updated**: 2026-01-03
 **Repository**: https://github.com/your-username/esp8266-weather-clock-opensource
@@ -1,440 +0,0 @@
 # Publishing to GitHub - Step by Step Guide
 This file contains instructions for publishing this project to GitHub.
 ## Prerequisites
 1. **GitHub account** - Sign up at https://github.com if you don't have one
 2. **Git installed** - Check with `git --version` in terminal
 3. **GitHub CLI (optional)** - Makes repository creation easier: https://cli.github.com/
 ---
 ## Option 1: Using GitHub Web Interface (Easiest)
 ### Step 1: Create Repository on GitHub
 1. Go to https://github.com/new
 2. Fill in:
   - **Repository name**: `esp8266-weather-clock-opensource`
   - **Description**: `Secure open-source firmware for ESP8266 weather clock - reverse engineered from AliExpress DIY kit`
   - **Visibility**: Public ✅
   - **Initialize**: ❌ Do NOT check "Add README" (we have one)
 3. Click: **Create repository**
 ### Step 2: Initialize Local Git Repository
 Open terminal and navigate to project directory:
 ```bash
 cd "/Users/apetrochenko/Library/Mobile Documents/com~apple~CloudDocs/src/arduino/clock/esp8266-weather-clock-opensource"
 ```
 Initialize git and add files:
 ```bash
 # Initialize git
 git init
 # Add all files
 git add .
 # Create first commit
 git commit -m "Initial commit: v1.9.1 production firmware
 - Complete reverse engineering of TJ-56-654 weather clock
 - Fixes security issues (WiFi password leak)
 - Fully async architecture (zero blocking)
 - OTA updates, web interface, REST API
 - Open-Meteo weather (free, no API key)
 - Comprehensive documentation"
 ```
 ### Step 3: Connect to GitHub
 Replace `YOUR_USERNAME` with your actual GitHub username:
 ```bash
 # Add remote
 git remote add origin https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource.git
 # Set main branch
 git branch -M main
 # Push to GitHub
 git push -u origin main
 ```
 **If prompted for credentials:**
 - Username: Your GitHub username
 - Password: Use **Personal Access Token** (not your password!)
  - Create token at: https://github.com/settings/tokens
  - Select scopes: `repo` (full control of private repositories)
 ### Step 4: Verify Upload
 1. Browse to: `https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource`
 2. You should see:
   - README.md rendered nicely
   - All directories and files
   - First commit visible
 ---
 ## Option 2: Using GitHub CLI (Faster)
 If you have GitHub CLI installed:
 ```bash
 # Navigate to project
 cd "/Users/apetrochenko/Library/Mobile Documents/com~apple~CloudDocs/src/arduino/clock/esp8266-weather-clock-opensource"
 # Authenticate (one-time)
 gh auth login
 # Create repo and push in one command
 gh repo create esp8266-weather-clock-opensource \
  --public \
  --source=. \
  --description="Secure open-source firmware for ESP8266 weather clock" \
  --push
 ```
 Done! Repository is created and pushed.
 ---
 ## Step 5: Configure Repository Settings
 ### Add Topics (Tags)
 1. Go to your repo on GitHub
 2. Click: **⚙️ Settings** (top right near About)
 3. Under "Topics", add:
   - `esp8266`
   - `arduino`
   - `iot`
   - `weather-station`
   - `reverse-engineering`
   - `security`
   - `oled-display`
   - `ntp`
   - `ota-updates`
   - `open-meteo`
 ### Update About Section
 1. Go to repo main page
 2. Click: **⚙️** (gear icon) next to "About"
 3. Set:
   - **Description**: `Secure open-source firmware for ESP8266 weather clock - reverse engineered from AliExpress DIY kit to fix security flaws`
   - **Website**: `https://open-meteo.com` (or your personal site if you blog about it)
   - **Topics**: Should already be set from above
 ### Enable Features
 In **Settings → General**:
 **Features**:
 - ✅ Issues (for bug reports)
 - ✅ Discussions (for questions)
 - ❌ Wiki (not needed, we have docs/)
 - ❌ Projects (not needed yet)
 **Pull Requests**:
 - ✅ Allow squash merging
 - ✅ Automatically delete head branches
 ### Set Up GitHub Actions
 The CI workflow should activate automatically on first push. Check:
 1. Go to: **Actions** tab
 2. You should see: "Build Firmware" workflow
 3. It should run and ✅ pass (compiles firmware)
 If it fails:
 - Check library names in `.github/workflows/build.yml`
 - Some libraries may need exact version pinning
 ---
 ## Step 6: Create First Release
 ### Tag the Release Locally
 ```bash
 # Create annotated tag
 git tag -a v1.9.1 -m "Release v1.9.1: Production-ready firmware
 Features:
 - Hybrid WiFi model (sync on boot, async in loop)
 - Daylight duration display
 - Fully async NTP, weather, WiFi reconnect
 - OTA updates, web interface, REST API
 - Open-Meteo weather (free API)
 - Security fixes (no WiFi password leak)
 Fixes:
 - Startup display blank for 10+ seconds
 - DNS resolution failed errors
 - Sunrise/sunset label cutoff"
 # Push tag to GitHub
 git push origin v1.9.1
 ```
 ### Create Release on GitHub
 1. Go to: **Releases** (right sidebar)
 2. Click: **Draft a new release**
 3. Fill in:
   - **Tag**: `v1.9.1` (should appear in dropdown)
   - **Release title**: `v1.9.1 - Production Ready`
   - **Description**:
     ```markdown
     ## 🎉 First Public Release
     Secure, open-source replacement firmware for ESP8266 weather clocks.
     ### ✨ Highlights
     - **Security**: Fixes WiFi password leak in original firmware
     - **Performance**: Fully async architecture, <1ms loop time
     - **Features**: OTA updates, web UI, REST API, NTP time, weather
     - **Free API**: Uses Open-Meteo (no registration required)
     ### 📦 Downloads
     - `esp8266-weather-clock-v1.9.1.bin` - Flash this via OTA or FTDI
     ### 📖 Documentation
     - [Installation Guide](docs/INSTALLATION.md)
     - [Hardware Specs](docs/HARDWARE.md)
     - [Full Changelog](CHANGELOG.md)
     ### 🚀 Quick Start
     1. Download `.bin` file
     2. Flash via FTDI (first time) or OTA (updates)
     3. Connect to `TJ56654-Setup` WiFi
     4. Configure your network
     5. Access web UI at `http://tj56654-clock.local`
     See [README](README.md) for complete instructions.
     ### 🐛 Known Issues
     None! This release is production-ready and tested 24/7.
     ```
 4. **Attach binary** (if you have it locally):
   - Compile firmware first: Arduino IDE → Sketch → Export Compiled Binary
   - Or use GitHub Actions artifact
   - Drag `build/clock_ntp_ota_v1.9.ino.bin` to release assets
   - Rename to: `esp8266-weather-clock-v1.9.1.bin`
 5. Click: **Publish release**
 ---
 ## Step 7: Add Shields/Badges to README
 Edit `README.md` and add at the top (after title):
 ```markdown
 <p align="center">
  <a href="https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource/releases">
    <img src="https://img.shields.io/github/v/release/YOUR_USERNAME/esp8266-weather-clock-opensource?style=flat-square" alt="Release">
  </a>
  <a href="https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource/blob/main/LICENSE">
    <img src="https://img.shields.io/github/license/YOUR_USERNAME/esp8266-weather-clock-opensource?style=flat-square" alt="License">
  </a>
  <a href="https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource/actions">
    <img src="https://img.shields.io/github/actions/workflow/status/YOUR_USERNAME/esp8266-weather-clock-opensource/build.yml?style=flat-square" alt="Build">
  </a>
  <a href="https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource/issues">
    <img src="https://img.shields.io/github/issues/YOUR_USERNAME/esp8266-weather-clock-opensource?style=flat-square" alt="Issues">
  </a>
 </p>
 ```
 Replace `YOUR_USERNAME` with actual username.
 Commit and push:
 ```bash
 git add README.md
 git commit -m "Add badges to README"
 git push
 ```
 ---
 ## Step 8: Share Your Project
 ### Post on Social Media
 **Reddit:**
 - r/esp8266
 - r/arduino
 - r/selfhosted
 - r/homeassistant (when you add HA integration)
 **Hackaday:**
 - Submit project tip: https://hackaday.com/submit-a-tip/
 **Hackster.io:**
 - Create project page: https://www.hackster.io/
 **Twitter/X:**
 ```
 Just reverse-engineered a $12 AliExpress weather clock and found it was leaking WiFi passwords!
 Replaced the firmware with secure open-source version:
 - ✅ No password leak
 - ✅ OTA updates
 - ✅ Free weather API
 - ✅ Full async arch
 Check it out: [your-repo-link]
 #ESP8266 #IoTSecurity #Arduino
 ```
 ### Add to Awesome Lists
 Search for "awesome ESP8266" and submit PR to add your project.
 ---
 ## Maintenance Tips
 ### Keep README Updated
 When you add features:
 1. Update README.md
 2. Update CHANGELOG.md
 3. Create new git tag
 4. Create GitHub release
 ### Respond to Issues
 Enable email notifications:
 1. Go to: repo → **Watch** → **Custom**
 2. Check: ✅ Issues, ✅ Pull requests, ✅ Discussions
 ### Version Numbering
 Use semantic versioning (semver.org):
 - `v2.0.0`: Breaking changes (incompatible config)
 - `v1.10.0`: New features (backward-compatible)
 - `v1.9.2`: Bug fixes only
 ### Automated Releases
 GitHub Actions can auto-build on new tags. Check `.github/workflows/build.yml`.
 ---
 ## Troubleshooting
 ### "Permission denied" when pushing
 **Solution**: Use Personal Access Token instead of password
 1. Generate: https://github.com/settings/tokens
 2. Scopes: `repo` (full control)
 3. Use token as password when prompted
 Or configure SSH keys:
 ```bash
 # Generate SSH key
 ssh-keygen -t ed25519 -C "your_email@example.com"
 # Add to GitHub: Settings → SSH Keys → New SSH key
 # Paste contents of ~/.ssh/id_ed25519.pub
 # Change remote to SSH
 git remote set-url origin git@github.com:YOUR_USERNAME/esp8266-weather-clock-opensource.git
 ```
 ### "This repository is empty"
 You forgot to push:
 ```bash
 git push -u origin main
 ```
 ### Files too large
 GitHub has 100MB file size limit. If you accidentally added build artifacts:
 ```bash
 # Remove from staging
 git reset HEAD build/
 # Add to .gitignore
 echo "build/" >> .gitignore
 # Commit
 git commit -m "Ignore build artifacts"
 ```
 ### CI build fails
 Check:
 - Library names are correct in `build.yml`
 - All libraries are available via Arduino Library Manager
 - Firmware compiles locally first
 ---
 ## Next Steps After Publishing
 1. **Star your own repo** (to make it discoverable)
 2. **Watch releases** (be notified of activity)
 3. **Enable Discussions** (for community Q&A)
 4. **Create SECURITY.md** (if you want responsible disclosure process)
 5. **Add funding links** (GitHub Sponsors, Buy Me a Coffee, etc.)
 ---
 ## GitHub Repository Best Practices
 ### Essential Files (✅ You have these!)
 - ✅ README.md
 - ✅ LICENSE
 - ✅ CONTRIBUTING.md
 - ✅ CHANGELOG.md
 - ✅ .gitignore
 - ✅ Issue templates
 ### Nice-to-Have
 - CODE_OF_CONDUCT.md (for community standards)
 - SECURITY.md (vulnerability disclosure policy)
 - FUNDING.yml (donation links)
 ### Pin Important Files
 On your repo page, pin:
 1. README.md (auto-pinned)
 2. INSTALLATION.md (pin in About section)
 3. Latest release (pin in sidebar)
 ---
 ## Success Checklist
 After publishing, verify:
 - [ ] Repository is public and accessible
 - [ ] README renders correctly (images, links work)
 - [ ] All documentation files are present
 - [ ] CI/CD pipeline passes (green checkmark)
 - [ ] First release is tagged and published
 - [ ] Binary is attached to release
 - [ ] Topics/tags are set
 - [ ] License is visible
 - [ ] Issues and Discussions are enabled
 ---
 **Congratulations!** Your project is now public and ready to help the world build secure IoT devices. 🚀
 ---
 **Repository URL**: https://github.com/YOUR_USERNAME/esp8266-weather-clock-opensource
 Don't forget to replace `YOUR_USERNAME` with your actual GitHub username!
@@ -27,7 +27,7 @@ I bought a cute weather clock kit from AliExpress ([TJ-56-654](https://pt.aliexp
 - [The Investigation](#the-investigation)
 - [The Solution: Custom Firmware](#the-solution-custom-firmware)
 - [Technical Deep Dive](#technical-deep-dive)
- [The Journey: v1.7 → v1.9.2](#the-journey-v17--v192)
+- [The Journey: v1.7 → v1.9.4](#the-journey-v17--v194)
 - [What's Next: Home Assistant Integration](#whats-next-home-assistant-integration)
 - [How to Flash This Firmware](#how-to-flash-this-firmware)
 - [Web Interface](#web-interface)
@@ -60,6 +60,7 @@ When you first set up the device, it creates an access point with a default pass
 5. **Your WiFi password is displayed in plaintext on the config page**
 Anyone within WiFi range could:
 - Connect to the device's AP (weak default password)
 - Browse to 192.168.4.1
 - Read your WiFi password in plaintext
@@ -78,13 +79,13 @@ This is a textbook example of poor IoT security design. No thanks.
 ### Original Hardware Specifications
-| Component | Details |
+| Component   | Details                                  |
-|-----------|---------|
+| ----------- | ---------------------------------------- |
-| **MCU** | ESP-01S (ESP8266EX, 1MB flash, 80KB RAM) |
+| **MCU**     | ESP-01S (ESP8266EX, 1MB flash, 80KB RAM) |
-| **Display** | GM009605v4.3 OLED (128x64, I2C) |
+| **Display** | GM009605v4.3 OLED (128x64, I2C)          |
-| **Power** | 5V USB (Micro-USB) |
+| **Power**   | 5V USB (Micro-USB)                       |
-| **Case** | Transparent acrylic (40x40x43mm) |
+| **Case**    | Transparent acrylic (40x40x43mm)         |
-| **PCB** | TJ-56-654 main board |
+| **PCB**     | TJ-56-654 main board                     |
 ### What It Came With
@@ -119,6 +120,7 @@ The transparent case made inspection easy - just unscrew the brass standoffs. In
 - **No additional sensors** (temperature/humidity were from weather API, not local)
 The ESP-01S pinout is printed right on the PCB:
 ```
 3V3  |  GND
 TX  |  GPIO0  (I2C SDA)
@@ -135,6 +137,7 @@ To flash custom firmware, you need:
 3. **Steady hands**
 **Wiring:**
 ```
 FTDI        ESP-01S
 ────────────────────
@@ -146,12 +149,14 @@ FTDI        ESP-01S
 ```
 **Boot into flash mode:**
 1. Connect GPIO0 to GND
 2. Power on the device
 3. Remove GPIO0 to GND connection after boot
 4. Device is now in programming mode
 **Programming:**
 - Use Arduino IDE with ESP8266 board support
 - Select board: "Generic ESP8266 Module"
 - Flash size: 1MB (FS:64KB OTA:~470KB)
@@ -176,6 +181,7 @@ I decided to write a complete replacement firmware with:
 ### Features Implemented
 #### 🌐 Network & Time
 - **WiFiManager** captive portal for secure first-time setup
 - **Hybrid WiFi**: Synchronous on boot (ensures proper init), async reconnect during operation
 - **NTP time sync** with configurable server and interval
@@ -183,12 +189,14 @@ I decided to write a complete replacement firmware with:
 - **mDNS**: Access via `http://tj56654-clock.local/`
 #### 🌦️ Weather Data
 - **Open-Meteo API**: Free, no registration, no API key
 - **Configurable location**: Latitude/longitude + city name
 - **Data**: Temperature, sunrise, sunset, daylight duration
 - **Smart updates**: Async fetch every 30 minutes (configurable)
 #### 🔄 OTA Updates
 - **Web-based OTA**: Upload .bin files via browser at `/update`
 - **ArduinoOTA**: Update directly from Arduino IDE
 - **Non-blocking**: System stays responsive during updates
@@ -245,33 +253,39 @@ All endpoints return JSON:
 The firmware uses **zero blocking operations** in the main loop. Everything is state-machine-based:
 #### Weather State Machine
 ```cpp
 enum WeatherState { IDLE, REQUESTING, SUCCESS, FAILED };
 ```
 Uses `AsyncHTTPRequest` library:
 - Non-blocking HTTP requests
 - Callback-based response handling
 - Exponential backoff on failures (1s → 2s → 4s)
 - Maximum 3 retries before giving up
 #### NTP State Machine
 ```cpp
 enum NTPState { IDLE, REQUEST_SENT, WAITING, SUCCESS, FAILED };
 ```
 Custom manual NTP implementation:
 - Builds raw UDP packets (48 bytes)
 - Non-blocking `parsePacket()` checks
 - 5-second timeout
 - Independent epoch tracking for accuracy between syncs
 #### WiFi State Machine
 ```cpp
 enum WiFiConnectionState { IDLE, CONNECTING, CONNECTED, FAILED };
 ```
 **Hybrid model** (this was critical!):
 - **Setup phase**: Synchronous connection (waits up to 10 seconds)
  - Why? OTA, web server, NTP all need WiFi ready
  - Without this, device shows blank display for 10+ seconds
@@ -282,11 +296,11 @@ enum WiFiConnectionState { IDLE, CONNECTING, CONNECTED, FAILED };
 ESP8266 has strict memory limits:
-| Memory Type | Total | Used | Usage | Status |
+| Memory Type | Total     | Used    | Usage   | Status      |
-|-------------|-------|------|-------|--------|
+| ----------- | --------- | ------- | ------- | ----------- |
-| **Flash** | 1,048,576 | 408,844 | 38% | ✅ Plenty |
+| **Flash**   | 1,048,576 | 408,844 | 38%     | ✅ Plenty   |
-| **RAM** | 80,192 | 37,644 | 46% | ✅ Safe |
+| **RAM**     | 80,192    | 37,644  | 46%     | ✅ Safe     |
-| **IRAM** | 65,536 | 61,987 | **94%** | ⚠️ Critical |
+| **IRAM**    | 65,536    | 61,987  | **94%** | ⚠️ Critical |
 **IRAM Crisis Solution:**
@@ -304,6 +318,7 @@ Applied to 26 functions (web handlers, display, config utilities), reducing IRAM
 **String Safety:**
 Avoid String concatenation in loops (causes heap fragmentation):
 ```cpp
 // ❌ BAD - 140+ concatenations
 String html = "";
@@ -353,29 +368,34 @@ struct Config {
 This took **3 firmware iterations** to get right:
 **v1.5**: Assumed TM1637 (7-segment LED driver)
 - ❌ Wrong - device has OLED, not 7-segment LEDs
 **v1.6**: Tried TM1650 (another LED driver)
 - ❌ Wrong - I2C addresses didn't match
 **v1.7**: Identified GM009605v4.3 (SSD1306-compatible OLED)
 - ✅ Correct! Used Adafruit_SSD1306 library
 - ✅ Discovered swapped pins: SDA on GPIO0, SCL on GPIO2
 **Pin mapping quirk:**
 Standard ESP8266 I2C uses GPIO4 (SDA) and GPIO5 (SCL), but ESP-01S only exposes GPIO0 and GPIO2. The board designer mapped:
 - GPIO0 → SDA (unusual)
 - GPIO2 → SCL (unusual)
 This is **backwards** from typical breakout boards, but works perfectly once configured:
 ```cpp
 Wire.begin(0, 2);  // SDA=GPIO0, SCL=GPIO2
 ```
 ---
-## The Journey: v1.7 → v1.9.2
+## The Journey: v1.7 → v1.9.4
 ### v1.7: Display Discovery ✅
@@ -389,6 +409,7 @@ Wire.begin(0, 2);  // SDA=GPIO0, SCL=GPIO2
 **Goals**: Fix memory issues, eliminate security holes
 **Changes:**
 - IRAM optimization (added `ICACHE_FLASH_ATTR` to 26 functions)
 - Removed hardcoded WiFi credentials
 - Fixed NTP interval bug (config value was ignored)
@@ -403,6 +424,7 @@ Wire.begin(0, 2);  // SDA=GPIO0, SCL=GPIO2
 **Goals**: Eliminate all blocking operations
 **Changes:**
 - Async HTTP weather fetch (AsyncHTTPRequest library)
 - Custom async NTP implementation (manual UDP packets)
 - Async WiFi connection (state machine)
@@ -411,12 +433,12 @@ Wire.begin(0, 2);  // SDA=GPIO0, SCL=GPIO2
 **Performance:**
-| Operation | Before (v1.8) | After (v1.9.0) | Improvement |
+| Operation      | Before (v1.8)  | After (v1.9.0) | Improvement         |
-|-----------|---------------|----------------|-------------|
+| -------------- | -------------- | -------------- | ------------------- |
-| Weather fetch | 1-10s blocking | 0ms | ✅ Async callback |
+| Weather fetch  | 1-10s blocking | 0ms            | ✅ Async callback   |
-| NTP sync | 5-20s blocking | 0ms | ✅ Non-blocking UDP |
+| NTP sync       | 5-20s blocking | 0ms            | ✅ Non-blocking UDP |
-| WiFi reconnect | 15s blocking | 0ms | ✅ State machine |
+| WiFi reconnect | 15s blocking   | 0ms            | ✅ State machine    |
-| Loop time | 10ms minimum | <1ms | ✅ 10x faster |
+| Loop time      | 10ms minimum   | <1ms           | ✅ 10x faster       |
 **Result**: Device stays responsive during OTA updates while weather is fetching!
@@ -429,6 +451,7 @@ After deploying v1.9.0, the display showed **blank screen for 10 seconds** after
 **Root Cause:**
 Making WiFi fully async broke the **initialization order**:
 ```cpp
 void setup() {
  setupWiFi();                   // Returns immediately (async)
@@ -440,18 +463,19 @@ void setup() {
 **Solution: Hybrid Model**
-| Phase | WiFi Mode | Blocking? | Why? |
+| Phase     | WiFi Mode    | Blocking? | Why?                        |
-|-------|-----------|-----------|------|
+| --------- | ------------ | --------- | --------------------------- |
-| `setup()` | Synchronous | 10s max | OTA/web/NTP need WiFi ready |
+| `setup()` | Synchronous  | 10s max   | OTA/web/NTP need WiFi ready |
-| `loop()` | Asynchronous | 0s | Don't freeze on reconnect |
+| `loop()`  | Asynchronous | 0s        | Don't freeze on reconnect   |
 **Results:**
 - ✅ Display shows time immediately after WiFi connects (~15 sec boot)
 - ✅ No "DNS resolution failed" errors
 - ✅ Proper initialization order guaranteed
 - ✅ Device never freezes on WiFi loss during operation
-### v1.9.2: WiFi Resilience (Current) 🛡️
+### v1.9.2: WiFi Resilience 🛡️
 **Problem Discovered:**
@@ -460,6 +484,7 @@ After WiFi outages, the device would **clear stored credentials** and enter AP m
 **Root Cause:**
 Aggressive credential clearing on connection failure:
 ```cpp
 if (wifiRetry.currentRetry >= wifiRetry.maxRetries) {
  memset(config.ssid, 0, sizeof(config.ssid));     // ❌ Clears credentials!
@@ -471,40 +496,43 @@ if (wifiRetry.currentRetry >= wifiRetry.maxRetries) {
 **Solution: Resilient WiFi**
-| Feature | Before (v1.9.1) | After (v1.9.2) |
+| Feature             | Before (v1.9.1)            | After (v1.9.2)                  |
-|---------|-----------------|----------------|
+| ------------------- | -------------------------- | ------------------------------- |
-| Credential clearing | After 5 failed attempts | Never |
+| Credential clearing | After 5 failed attempts    | Never                           |
-| Retry strategy | Give up after 5 tries | Infinite with backoff |
+| Retry strategy      | Give up after 5 tries      | Infinite with backoff           |
-| Max retry interval | N/A | 5 minutes |
+| Max retry interval  | N/A                        | 5 minutes                       |
-| Fallback AP | After clearing credentials | After ~5 min (dual STA+AP mode) |
+| Fallback AP         | After clearing credentials | After ~5 min (dual STA+AP mode) |
-| Clock during outage | Blank display | Shows last synced time |
+| Clock during outage | Blank display              | Shows last synced time          |
 **Key Changes:**
 - **Never clear credentials** on connection failure
 - **Exponential backoff**: 5s → 10s → 20s → ... → 5min max
 - **Fallback AP** ("TJ56654-Setup") enabled after ~5 min, while still retrying
 - **Dual STA+AP mode**: Device continues reconnect attempts while AP is active
- **SDK credentials support**: Tries WiFiManager-stored credentials first, then EEPROM
+- **SDK credentials**: Used only on first boot (no saved SSID); subsequent boots go straight to saved credentials
 - **"No WiFi" display**: Shows retry countdown instead of cryptic numbers
 - **"!" indicator**: Shown in date line when WiFi disconnected
 **Network Activity Summary:**
-| Service | Interval | Endpoint | Protocol |
+| Service | Interval   | Endpoint           | Protocol      |
-|---------|----------|----------|----------|
+| ------- | ---------- | ------------------ | ------------- |
-| NTP | 1 hour | pool.ntp.org:123 | UDP |
+| NTP     | 1 hour     | pool.ntp.org:123   | UDP           |
-| Weather | 30 min | api.open-meteo.com | HTTP |
+| Weather | 30 min     | api.open-meteo.com | HTTP          |
-| mDNS | continuous | 224.0.0.251 | UDP multicast |
+| mDNS    | continuous | 224.0.0.251        | UDP multicast |
 ~50 requests/day total.
 **Results:**
 - ✅ Credentials persist through WiFi outages
 - ✅ Device automatically reconnects when WiFi returns
 - ✅ Clock continues running with last synced time
 - ✅ User can reconfigure via fallback AP if needed
 **Startup Timeline:**
 ```
 [0-5s]   Display init, startup animation
 [5-15s]  WiFi connection (SYNCHRONOUS in setup())
@@ -515,15 +543,40 @@ if (wifiRetry.currentRetry >= wifiRetry.maxRetries) {
         ✅ Time synced and displayed
 ```
 ### v1.9.3: Modular Architecture 🗂️
 Split monolithic 2,100-line `.ino` into focused modules:
 | File                | Responsibility                          |
 | ------------------- | --------------------------------------- |
 | `weather_clock.ino` | Entry point: `setup()` and `loop()`     |
 | `config.h`          | Config struct, EEPROM layout, constants |
 | `globals.h`         | Shared state and extern declarations    |
 | `display.cpp`       | OLED rendering                          |
 | `ntp_client.cpp`    | Async NTP sync                          |
 | `weather.cpp`       | Open-Meteo API fetch                    |
 | `web_server.cpp`    | Web UI and REST API                     |
 | `wifi_manager.cpp`  | WiFi connection and resilience          |
 ### v1.9.4: Bug Fixes & Cleanup ✅ (Current)
 Community-reported bugs fixed:
 - **Date timezone** (#5): Date now changes at local midnight, not UTC midnight
 - **Weather refresh** (#7): Periodic weather updates no longer blocked after first fetch
 - **WiFi hotspot** (#3): Device no longer connects to open SDK-cached networks (e.g. public hotspots) when a saved SSID exists, preventing config corruption
 - **ArduinoJson v7**: Updated `StaticJsonDocument` → `JsonDocument` for library compatibility
 - **Compiler warnings**: Removed unused variable, fixed sprintf buffer size
 ### Memory Evolution
-| Version | RAM Usage | IRAM Usage | Flash Usage | Notes |
+| Version | RAM Usage    | IRAM Usage       | Flash Usage   | Notes                 |
-|---------|-----------|------------|-------------|-------|
+| ------- | ------------ | ---------------- | ------------- | --------------------- |
-| v1.7 | 34,980 (43%) | **61,987 (94%)** | 407,500 (38%) | IRAM crisis |
+| v1.7    | 34,980 (43%) | **61,987 (94%)** | 407,500 (38%) | IRAM crisis           |
-| v1.8 | 36,980 (46%) | **45,120 (68%)** | 407,800 (38%) | ICACHE_FLASH_ATTR fix |
+| v1.8    | 36,980 (46%) | **45,120 (68%)** | 407,800 (38%) | ICACHE_FLASH_ATTR fix |
-| v1.9.0 | 37,516 (46%) | **61,987 (94%)** | 408,540 (38%) | Async libs added |
+| v1.9.0  | 37,516 (46%) | **61,987 (94%)** | 408,540 (38%) | Async libs added      |
-| v1.9.1 | 37,644 (46%) | **61,987 (94%)** | 408,844 (38%) | Hybrid WiFi fix |
+| v1.9.1  | 37,644 (46%) | **61,987 (94%)** | 408,844 (38%) | Hybrid WiFi fix       |
-| v1.9.2 | 37,800 (47%) | **61,987 (94%)** | 409,100 (39%) | WiFi resilience |
+| v1.9.2  | 37,800 (47%) | **61,987 (94%)** | 409,100 (39%) | WiFi resilience       |
 **Verdict**: Stable memory usage, no leaks detected after 24h+ uptime tests.
@@ -536,6 +589,7 @@ The firmware is designed to be extensible. Next planned features:
 ### Custom Display Screens
 Pull data from Home Assistant via REST API:
 - **Smart home stats**: Energy usage, room temperatures
 - **Sensor data**: Air quality, CO2 levels
 - **Automation states**: Alarm status, door locks
@@ -549,6 +603,7 @@ Pull data from Home Assistant via REST API:
 ### WebSocket Live Updates
 Replace polling with WebSocket for:
 - Real-time config changes without page refresh
 - Live display preview in web UI
 - Push notifications for firmware updates
@@ -579,6 +634,7 @@ Replace polling with WebSocket for:
     - `WiFiManager` (by tzapu)
     - `AsyncHTTPRequest_Generic`
     - `ESPAsyncTCP`
     - `ArduinoJson` (by Benoit Blanchon)
 3. **Board Configuration**
   - Board: "Generic ESP8266 Module"
@@ -591,6 +647,7 @@ Replace polling with WebSocket for:
 ### First Flash (via FTDI)
 1. **Wire the ESP-01S**:
   ```
   FTDI 3.3V  →  ESP-01S 3V3
   FTDI GND   →  ESP-01S GND
@@ -600,7 +657,7 @@ Replace polling with WebSocket for:
   ```
 2. **Compile and Upload**:
-   - Open `clock_ntp_ota_v1.9.ino`
+   - Open `weather_clock.ino`
   - Sketch → Upload
   - Wait for "Done uploading"
   - Remove GPIO0-to-GND jumper
@@ -633,6 +690,7 @@ Replace polling with WebSocket for:
 ## Web Interface
 ### Home Page (`/`)
 Current time display with live updates via JavaScript (fetches `/api/time` every second).
 ### Configuration Page (`/config`)
@@ -640,11 +698,13 @@ Current time display with live updates via JavaScript (fetches `/api/time` every
 Comprehensive settings form:
 **WiFi Settings**
 - SSID
 - Password
 - Hostname (for mDNS)
 **Time Settings**
 - Timezone offset (seconds from UTC)
 - DST enabled (European rules)
 - NTP server address
@@ -652,6 +712,7 @@ Comprehensive settings form:
 - Hour format (12h/24h)
 **Weather Settings**
 - Enabled/disabled toggle
 - Latitude
 - Longitude
@@ -659,6 +720,7 @@ Comprehensive settings form:
 - Update interval (seconds)
 **Display Settings**
 - Brightness (0-7)
 - Rotation (0°, 90°, 180°, 270°)
 - Display rotation interval (seconds)
@@ -692,6 +754,7 @@ All endpoints return JSON (except `/update` which is for file upload).
 Current time information.
 **Response:**
 ```json
 {
  "current": "14:23:45",
@@ -707,6 +770,7 @@ Current time information.
 System status overview.
 **Response:**
 ```json
 {
  "wifi": {
@@ -733,6 +797,7 @@ System status overview.
 Current weather data.
 **Response:**
 ```json
 {
  "temperature": 15.4,
@@ -751,6 +816,7 @@ Current weather data.
 Export full configuration as JSON.
 **Response:**
 ```json
 {
  "ssid": "MyNetwork",
@@ -780,6 +846,7 @@ Import configuration from JSON.
 **Request Body**: Same structure as export response (password field optional for security).
 **Response:**
 ```json
 {
  "status": "ok"
@@ -793,6 +860,7 @@ Device automatically reboots after import.
 Factory reset (clears EEPROM).
 **Response:**
 ```json
 {
  "status": "cleared"
@@ -806,6 +874,7 @@ Device reboots to WiFiManager captive portal.
 Remote reboot.
 **Response:**
 ```json
 {
  "status": "rebooting"
@@ -820,15 +889,15 @@ Device reboots immediately.
 ### What Changed from Original Firmware
-| Issue | Original | Custom Firmware |
+| Issue                  | Original                       | Custom Firmware                   |
-|-------|----------|-----------------|
+| ---------------------- | ------------------------------ | --------------------------------- |
-| **WiFi Password Leak** | Plaintext in open AP | No open AP after setup |
+| **WiFi Password Leak** | Plaintext in open AP           | No open AP after setup            |
-| **Persistent AP** | Always active | Only on first boot or failure |
+| **Persistent AP**      | Always active                  | Only on first boot or failure     |
-| **API Keys** | QWeather requires registration | Open-Meteo (no key needed) |
+| **API Keys**           | QWeather requires registration | Open-Meteo (no key needed)        |
-| **Cloud Dependency** | Chinese servers | Direct API calls, no intermediary |
+| **Cloud Dependency**   | Chinese servers                | Direct API calls, no intermediary |
-| **Firmware Updates** | Manual FTDI only | OTA via WiFi (password-protected) |
+| **Firmware Updates**   | Manual FTDI only               | OTA via WiFi (password-protected) |
-| **Config Access** | No authentication | Admin password required |
+| **Config Access**      | No authentication              | Admin password required           |
-| **Code Transparency** | Closed source | Open source (you're reading it!) |
+| **Code Transparency**  | Closed source                  | Open source (you're reading it!)  |
 ### Best Practices Implemented
@@ -842,16 +911,19 @@ Device reboots immediately.
 ### Recommended Post-Flash Steps
 1. **Change OTA password**: Edit line ~60 in `.ino` file:
   ```cpp
   ArduinoOTA.setPassword("admin");  // Change this!
   ```
 2. **Change web admin password**: Edit line ~430:
   ```cpp
   if (!server.authenticate("admin", "admin")) {  // Change this!
   ```
 3. **Set strong WiFi AP fallback password**: Edit line ~780:
   ```cpp
   WiFi.softAP("TJ56654-Clock", "12345678");  // Change this!
   ```
@@ -900,6 +972,7 @@ Device reboots immediately.
 **Firmware**: Written from scratch with love and frustration
 **Libraries Used**:
 - [ESP8266 Arduino Core](https://github.com/esp8266/Arduino)
 - [Adafruit SSD1306](https://github.com/adafruit/Adafruit_SSD1306)
 - [WiFiManager](https://github.com/tzapu/WiFiManager)
@@ -907,9 +980,11 @@ Device reboots immediately.
 - [NTPClient](https://github.com/arduino-libraries/NTPClient)
 **APIs**:
 - [Open-Meteo](https://open-meteo.com/) - Free weather API, no registration required
 **Tools**:
 - Arduino IDE 2.x
 - FTDI FT232RL USB-to-Serial adapter
 - Lots of coffee ☕
@@ -921,14 +996,11 @@ Device reboots immediately.
 ```
 esp8266-weather-clock/
 ├── firmware/
-│   └── clock_ntp_ota_v1.9/
+│   └── weather_clock/
-│       └── clock_ntp_ota_v1.9.ino  # Main firmware (~2,100 lines)
+│       └── weather_clock.ino       # Main firmware (~2,100 lines)
 ├── docs/
 │   ├── HARDWARE.md                 # Hardware specifications
-│   ├── INSTALLATION.md             # Flashing guide
+│   └── INSTALLATION.md             # Flashing guide
 │   ├── v1.9_RELEASE_NOTES.md       # v1.9.0 async refactoring
 │   ├── v1.9.1_HYBRID_FIX.md        # WiFi startup fix
 │   └── v1.9.2_WIFI_RESILIENCE.md   # WiFi resilience documentation
 ├── CHANGELOG.md                    # Version history
 └── README.md                       # This file
 ```
@@ -946,6 +1018,7 @@ This project is released into the public domain. Do whatever you want with it. I
 This project started as "I don't trust this device" and ended as "I built something better."
 The original firmware had security holes you could drive a truck through. The custom replacement:
 - ✅ Doesn't leak WiFi passwords
 - ✅ Uses free, open APIs
 - ✅ Updates over WiFi
@@ -965,4 +1038,4 @@ Now go make something cool. 🚀
 **Author**: apetrochenko
 **Date**: 2026-01-06
-**Firmware Version**: v1.9.2 (Production Ready)
+**Firmware Version**: v1.9.4 (Production Ready)
@@ -64,16 +64,17 @@ Go to: **Sketch → Include Library → Manage Libraries**
 Install the following libraries (search by name):
-| Library | Author | Min Version | Purpose |
+| Library                      | Author           | Min Version | Purpose                       |
-|---------|--------|-------------|---------|
+| ---------------------------- | ---------------- | ----------- | ----------------------------- |
-| **Adafruit GFX Library** | Adafruit | 1.11.0 | Graphics primitives |
+| **Adafruit GFX Library**     | Adafruit         | 1.11.0      | Graphics primitives           |
-| **Adafruit SSD1306** | Adafruit | 2.5.0 | OLED display driver |
+| **Adafruit SSD1306**         | Adafruit         | 2.5.0       | OLED display driver           |
-| **NTPClient** | Fabrice Weinberg | 3.2.0 | NTP time sync (base) |
+| **NTPClient**                | Fabrice Weinberg | 3.2.0       | NTP time sync (base)          |
-| **WiFiManager** | tzapu | 2.0.0 | Captive portal setup |
+| **WiFiManager**              | tzapu            | 2.0.0       | Captive portal setup          |
-| **AsyncHTTPRequest_Generic** | Khoi Hoang | 1.13.0 | Async weather fetch |
+| **AsyncHTTPRequest_Generic** | Khoi Hoang       | 1.13.0      | Async weather fetch           |
-| **ESPAsyncTCP** | me-no-dev | 1.2.2 | Async TCP (required by above) |
+| **ESPAsyncTCP**              | me-no-dev        | 1.2.2       | Async TCP (required by above) |
 **Installation steps for each library:**
 1. Search library name in Library Manager
 2. Click **Install**
 3. Wait for "INSTALLED" badge
@@ -87,17 +88,17 @@ Install the following libraries (search by name):
 2. Select: **Generic ESP8266 Module**
 3. Configure settings:
-| Setting | Value | Why |
+| Setting           | Value                      | Why                                      |
-|---------|-------|-----|
+| ----------------- | -------------------------- | ---------------------------------------- |
-| Flash Size | `1MB (FS:64KB OTA:~470KB)` | Enables OTA with 470KB max firmware |
+| Flash Size        | `1MB (FS:64KB OTA:~470KB)` | Enables OTA with 470KB max firmware      |
-| Flash Mode | `DIO` | Compatible with most ESP-01S modules |
+| Flash Mode        | `DIO`                      | Compatible with most ESP-01S modules     |
-| Flash Frequency | `40MHz` | Safe default for all ESP8266 |
+| Flash Frequency   | `40MHz`                    | Safe default for all ESP8266             |
-| CPU Frequency | `80MHz` | Standard (can use 160MHz for more speed) |
+| CPU Frequency     | `80MHz`                    | Standard (can use 160MHz for more speed) |
-| Crystal Frequency | `26MHz` | Default for ESP-01S |
+| Crystal Frequency | `26MHz`                    | Default for ESP-01S                      |
-| Upload Speed | `115200` | Balance between speed and reliability |
+| Upload Speed      | `115200`                   | Balance between speed and reliability    |
-| Debug Level | `None` | Reduces firmware size |
+| Debug Level       | `None`                     | Reduces firmware size                    |
-| IwIP Variant | `v2 Lower Memory` | Better for 1MB flash devices |
+| IwIP Variant      | `v2 Lower Memory`          | Better for 1MB flash devices             |
-| Erase Flash | `Only Sketch` | Preserves config on re-flash |
+| Erase Flash       | `Only Sketch`              | Preserves config on re-flash             |
 ---
@@ -106,6 +107,7 @@ Install the following libraries (search by name):
 ### Step 1: Identify Pins
 ESP-01S pinout (looking at module from top, antenna up):
 ```
       ┌─────────────┐
       │             │
@@ -123,15 +125,16 @@ ESP-01S pinout (looking at module from top, antenna up):
 **Connections:**
-| FTDI Pin | ESP-01S Pin | Wire Color | Notes |
+| FTDI Pin | ESP-01S Pin | Wire Color | Notes                             |
-|----------|-------------|------------|-------|
+| -------- | ----------- | ---------- | --------------------------------- |
-| 3.3V | 3V3 | Red | Power (NOT 5V!) |
+| 3.3V     | 3V3         | Red        | Power (NOT 5V!)                   |
-| GND | GND | Black | Ground |
+| GND      | GND         | Black      | Ground                            |
-| TX | RX | Yellow | Data: FTDI transmit → ESP receive |
+| TX       | RX          | Yellow     | Data: FTDI transmit → ESP receive |
-| RX | TX | Green | Data: FTDI receive → ESP transmit |
+| RX       | TX          | Green      | Data: FTDI receive → ESP transmit |
-| GND | GPIO0 | Blue | **Programming mode** (temporary) |
+| GND      | GPIO0       | Blue       | **Programming mode** (temporary)  |
 **⚠️ CRITICAL**:
 - **Never connect 5V to ESP-01S** - it's not 5V tolerant!
 - Double-check polarity before powering on
 - GPIO0-to-GND connection is **temporary** (only for programming mode)
@@ -152,8 +155,8 @@ ESP-01S is now in programming mode, ready to receive firmware.
 ### Step 1: Open Project
 1. Download or clone this repository
-2. Navigate to: `esp8266-weather-clock-opensource/src/`
+2. Navigate to: `esp8266-weather-clock-opensource/firmware/weather_clock/`
-3. Open: `clock_ntp_ota_v1.9.ino` in Arduino IDE
+3. Open: `weather_clock.ino` in Arduino IDE
 ### Step 2: Verify Board Settings
@@ -166,6 +169,7 @@ ESP-01S is now in programming mode, ready to receive firmware.
   - Windows: `COM3`, `COM4`, etc.
 If port doesn't appear:
 - Check USB cable is data-capable (not charge-only)
 - Install FTDI drivers
 - Try different USB port
@@ -222,10 +226,12 @@ If port doesn't appear:
 ### Step 2: Captive Portal
 **Automatic (iOS/Android):**
 - Captive portal should pop up automatically
 - If not, manually browse to: http://192.168.4.1
 **Manual (laptop):**
 - Browse to: http://192.168.4.1
 ### Step 3: Configure WiFi
@@ -240,16 +246,19 @@ If port doesn't appear:
 ### Step 4: Find Device IP
 **Method 1: Router Admin Panel**
 - Log into your router
 - Look for device: "tj56654-clock"
 - Note its IP address (e.g., 192.168.1.47)
 **Method 2: mDNS (if your OS supports it)**
 - Browse to: http://tj56654-clock.local/
 - Works on macOS, Linux, iOS out-of-box
 - Windows: Install [Bonjour Print Services](https://support.apple.com/kb/DL999)
 **Method 3: Serial Monitor**
 1. Keep FTDI connected (no GPIO0 to GND!)
 2. Open: **Tools → Serial Monitor**
 3. Set baud rate: **115200**
@@ -261,6 +270,7 @@ If port doesn't appear:
 Browse to: `http://<device-ip>/` or `http://tj56654-clock.local/`
 You should see:
 - Current time display
 - Navigation links (Config, Debug, Update)
@@ -276,6 +286,7 @@ You should see:
 4. Device reboots with new settings
 **Timezone examples:**
 - UTC+0 (London winter): `0`
 - UTC+1 (Paris winter): `3600`
 - UTC-5 (New York winter): `-18000`
@@ -319,6 +330,7 @@ curl -u admin:admin -F "file=@/path/to/firmware.bin" http://192.168.x.x/update
 ```
 Replace:
 - `192.168.x.x` with your device IP
 - `/path/to/firmware.bin` with actual path to .bin file
@@ -329,43 +341,51 @@ Replace:
 ### Upload Fails
 **Error: "espcomm_open failed"**
 - Check: GPIO0 was grounded during power-on
 - Check: FTDI driver installed
 - Try: Different USB port
 - Try: Lower upload speed (57600 instead of 115200)
 **Error: "espcomm_upload_mem failed"**
 - Check: Wire connections (especially RX↔TX swap)
 - Check: FTDI is 3.3V (not 5V)
 - Try: Power ESP-01S from external 3.3V supply (FTDI may not provide enough current)
 **Error: "Chip sync error"**
 - GPIO0 must be LOW during boot
 - Try: Hold GPIO0 to GND, reset ESP, then release GPIO0
 ### Compilation Fails
 **Error: "library not found"**
 - Install missing library via Library Manager
 - Restart Arduino IDE after installing
 **Error: "Sketch too big"**
 - Flash size must be set to 1MB
 - Reduce features if necessary (disable weather, etc.)
 **IRAM overflow error**
 - Some functions missing `ICACHE_FLASH_ATTR`
 - Use version from this repo (already optimized)
 ### WiFi Connection Fails
 **Device creates AP but won't connect to home WiFi**
 - ESP8266 only supports 2.4GHz (not 5GHz)
 - Try: Different WiFi channel (1, 6, or 11)
 - Check: WiFi password is correct
 - Check: Router supports 802.11n
 **Device reboots in a loop**
 - Likely: Power supply too weak (brownout)
 - Solution: Use powered USB hub or different power adapter
 - Minimum: 500mA @ 5V
@@ -373,28 +393,33 @@ Replace:
 ### Display Issues
 **Display is blank**
 - Check: I2C wiring (SDA=GPIO0, SCL=GPIO2)
 - Check: Display I2C address (try 0x3C and 0x3D in code)
 - Test: Use `/api/i2c-scan` endpoint to detect display
 **Display shows garbage**
 - Wrong display library or initialization
 - This firmware is for SSD1306-compatible OLED
 - Verify display model is GM009605v4.3 or similar
 **Display is upside down**
 - Change `display_orientation` in `/config`
 - Values: 0 (normal), 1 (90°), 2 (180°), 3 (270°)
 ### Time Not Syncing
 **Time shows 00:00:00**
 - Check: WiFi is connected (`/api/status`)
 - Check: NTP server is reachable (default: pool.ntp.org)
 - Check: Router firewall allows UDP port 123
 - Try: Different NTP server (e.g., time.google.com)
 **Time is wrong by hours**
 - Check: Timezone offset in `/config`
 - Remember: Offset is in **seconds**, not hours
  - Example: UTC+1 = 3600 seconds
@@ -402,6 +427,7 @@ Replace:
 ### Weather Not Updating
 **Temperature shows 0.0°C**
 - Check: Internet connectivity (`/api/debug`)
 - Check: Latitude/longitude are correct
 - Check: Open-Meteo API is accessible (visit https://open-meteo.com/ in browser)
@@ -410,11 +436,13 @@ Replace:
 ### OTA Update Fails
 **Web upload hangs at 0%**
 - Check: Device is online and responsive
 - Try: Smaller firmware (disable features)
 - Try: Upload via Arduino IDE instead
 **Upload completes but device doesn't reboot**
 - Wait 30 seconds (sometimes slow)
 - Manually power cycle device
 - Check serial output for errors
@@ -422,10 +450,12 @@ Replace:
 ### Serial Monitor Shows Errors
 **"DNS resolution failed"**
 - In v1.9.0 (fixed in v1.9.1)
 - Upgrade to v1.9.1 or later
 **Watchdog reset / exception**
 - Likely: Code bug or memory corruption
 - Check: IRAM usage < 95%
 - Report: Open issue with serial log
@@ -437,6 +467,7 @@ Replace:
 ### Change OTA Password
 Edit in source code (line ~60):
 ```cpp
 ArduinoOTA.setPassword("your-secret-password");
 ```
@@ -444,6 +475,7 @@ ArduinoOTA.setPassword("your-secret-password");
 ### Change Web Admin Password
 Edit in source code (line ~430):
 ```cpp
 if (!server.authenticate("admin", "your-secret-password")) {
 ```
@@ -453,13 +485,16 @@ if (!server.authenticate("admin", "your-secret-password")) {
 To save memory, disable unused features:
 **Disable weather:**
 - Set `weather_enabled = false` in `/config`
 - Or remove weather code from source
 **Disable sunrise/sunset:**
 - Set `show_sunrise_sunset = false` in `/config`
 **Disable display rotation:**
 - Set `display_rotation_sec = 0` (manual switch only)
 ---
@@ -1,218 +0,0 @@
 # v1.9.1 - Hybrid Async Fix
 ## Problem in v1.9.0
 **Symptoms:**
 - Display shows blank screen ~10 seconds after boot
 - "DNS resolution failed" errors in logs
 - Time appears only after 10+ seconds
 **Root Cause:**
 ```cpp
 void setup() {
  loadConfig();
  setupWiFi();              // Returns IMMEDIATELY (async)
  setupOTA();               // WiFi NOT ready!
  setupWebServer();         // WiFi NOT ready!
  testInternetConnectivity(); // WiFi NOT ready! -> "DNS resolution failed"
 }
 ```
 WiFi became **fully asynchronous**, but this is **wrong for setup()**:
 - OTA, web server, NTP **require a ready WiFi connection**
 - `testInternetConnectivity()` ran **before WiFi connected**
 - Time on display appeared only when async WiFi finally connected
 ## Solution: Hybrid Model
 | Phase | WiFi Mode | Blocking | Reason |
 |-------|-----------|----------|--------|
 | **setup()** | **Synchronous** | 10 sec | Required for OTA/web/NTP initialization |
 | **loop()** | **Asynchronous** | 0 sec | Don't freeze on reconnect |
 ### Code Changes
 #### 1. setupWiFi() - Now Synchronous
 ```cpp
 void ICACHE_FLASH_ATTR setupWiFi() {
  Serial.println("WiFi Setup - Synchronous for initial connection");
  WiFi.hostname(config.hostname);
  if (strlen(config.ssid) > 0) {
    WiFi.mode(WIFI_STA);
    WiFi.begin(config.ssid, config.password);
    // SYNCHRONOUS wait (max 10 seconds)
    int attempts = 0;
    while (WiFi.status() != WL_CONNECTED && attempts < 20) {
      delay(500);
      showNumber(attempts, false);  // Show progress on display
      attempts++;
    }
    if (WiFi.status() == WL_CONNECTED) {
      // WiFi ready for OTA/web/NTP!
      showIP();
      wifiConnState = WIFI_CONN_CONNECTED;
      return;
    }
  }
  // Fallback to WiFiManager if credentials didn't work
  // ...
 }
 ```
 #### 2. loop() - Async Reconnect
 ```cpp
 void loop() {
  // WiFi reconnection (async, non-blocking)
  static unsigned long lastWiFiCheck = 0;
  if (millis() - lastWiFiCheck > 5000) {
    if (WiFi.status() != WL_CONNECTED && wifiConnState == WIFI_CONN_CONNECTED) {
      Serial.println("WiFi disconnected, attempting async reconnect...");
      WiFi.begin();  // Async reconnect
      wifiConnState = WIFI_CONN_CONNECTING;
      wifiConnectStart = millis();
    }
    lastWiFiCheck = millis();
  }
  processWiFiConnection();  // Async reconnect handling
  // Other async operations
  processNTPResponse();
  fetchWeatherAsync();
  // ...
 }
 ```
 ## Test Results
 ### Before (v1.9.0)
 ```
 [0-5s]   -> Display init
 [5-15s]  -> WiFi connecting (async, setup() returns immediately)
 [15-20s] -> OTA/web init WITHOUT WiFi -> Errors!
 [20s]    -> testInternetConnectivity() WITHOUT WiFi -> "DNS resolution failed"
 [15-25s] -> WiFi finally connects (async)
 [25-30s] -> NTP sync begins
 Display blank for 10+ seconds
 "DNS resolution failed" errors
 ```
 ### After (v1.9.1)
 ```
 [0-5s]   -> Display init + startup animation
 [5-15s]  -> WiFi connection (SYNCHRONOUS, setup() waits)
            WiFi connected!
 [15-20s] -> OTA/web/NTP init WITH WiFi
            Internet test: PASSED
            No DNS errors!
 [20-30s] -> First async NTP sync
            Time synced!
 Display shows time immediately after WiFi connects (~15 sec)
 No "DNS resolution failed" errors
 Proper initialization order
 ```
 ## Startup Timeline
 ```
 +----------------------------------------------------------+
 | SETUP PHASE (Synchronous WiFi)                           |
 +----------------------------------------------------------+
 |                                                          |
 |  [0s]  +-------------+                                   |
 |        |  Display    |  Startup animation                |
 |  [5s]  |    Init     |  "Weather Clock v1.9.1"           |
 |        +-------------+                                   |
 |                                                          |
 |  [5s]  +---------------------------------+               |
 |        |  WiFi Connect (SYNCHRONOUS)     |               |
 |        |  - Connecting to network...     |               |
 | [15s]  |  - Connected! IP assigned       |               |
 |        +---------------------------------+               |
 |               |                                          |
 |        WiFi is READY here                                |
 |               |                                          |
 | [15s]  +---------------------------------+               |
 |        |  OTA Init      (needs WiFi)     |               |
 |        |  Web Server    (needs WiFi)     |               |
 | [20s]  |  NTP Client    (needs WiFi)     |               |
 |        |  Internet Test (needs WiFi)     |               |
 |        +---------------------------------+               |
 |                                                          |
 | [20s]  Setup complete! -> loop() starts                  |
 |                                                          |
 +----------------------------------------------------------+
 +----------------------------------------------------------+
 | LOOP PHASE (Async Operations)                            |
 +----------------------------------------------------------+
 |                                                          |
 |  [Every loop]  +------------------------+                |
 |                |  WiFi Health Check     |                |
 |                |  (every 5 sec)         |                |
 |                |  If disconnected:      |                |
 |                |  -> Async reconnect    |                |
 |                +------------------------+                |
 |                                                          |
 |  [Every loop]  +------------------------+                |
 |                |  Async NTP Processing  |                |
 |                |  (non-blocking)        |                |
 |                +------------------------+                |
 |                                                          |
 |  [Every 30m]   +------------------------+                |
 |                |  Async Weather Fetch   |                |
 |                |  (non-blocking)        |                |
 |                +------------------------+                |
 |                                                          |
 |  Loop time: <1ms (no blocking!)                          |
 |                                                          |
 +----------------------------------------------------------+
 ```
 ## Benefits of Hybrid Approach
 ### In setup():
 1. **Correct initialization order** - WiFi -> OTA -> web -> NTP
 2. **No DNS errors** - internet connectivity test runs AFTER WiFi
 3. **Predictable behavior** - setup() completes when everything is ready
 4. **Display shows time immediately** - no need to wait for async WiFi
 ### In loop():
 1. **No freeze on reconnect** - async handling of WiFi loss
 2. **Async NTP** - doesn't block loop
 3. **Async weather** - doesn't block loop
 4. **Exponential backoff** - smart retry on errors
 5. **Loop <1ms** - always responsive device
 ## Memory
 | Resource | v1.9.0 | v1.9.1 | Change |
 |----------|--------|--------|--------|
 | RAM    | 37,516 | 37,644 | +128 bytes |
 | IRAM   | 61,987 | 61,987 | 0 bytes |
 | Flash  | 408,540 | 408,844 | +304 bytes |
 Minimal memory changes (+0.3%) for critical UX improvement.
 ## Conclusion
 **v1.9.1 implements the ideal balance:**
 - Setup: Synchronous for reliable initialization
 - Loop: Asynchronous for responsiveness
 **Result:**
 - Display shows time after 15 sec (instead of 25+ sec)
 - No "DNS resolution failed" errors
 - Correct startup order
 - Device doesn't freeze on WiFi loss during operation
 **Status**: Production ready
@@ -1,313 +0,0 @@
 # v1.9.2 - WiFi Resilience
 ## Problem in v1.9.1
 **Symptoms:**
 - After WiFi outage (router restart, temporary network issues), device enters AP mode
 - WiFi credentials are cleared, requiring manual reconfiguration
 - User must reconnect to "TJ56654-Setup" AP and re-enter WiFi password
 - This happens every time WiFi goes down temporarily
 **Root Cause:**
 Aggressive credential clearing after connection failures:
 ```cpp
 void processWiFiConnection() {
  // After 5 failed attempts...
  if (wifiRetry.currentRetry >= wifiRetry.maxRetries) {
    // Clear credentials!
    memset(config.ssid, 0, sizeof(config.ssid));
    memset(config.password, 0, sizeof(config.password));
    saveConfig();
    // Start AP mode for reconfiguration
    WiFiManager wm;
    wm.startConfigPortal("TJ56654-Setup", "12345678");
  }
 }
 ```
 **Impact:**
 - Poor user experience during network outages
 - Unnecessary manual intervention required
 - Device unusable until reconfigured
 ## Solution: Resilient WiFi
 ### Key Changes
 | Feature | Before (v1.9.1) | After (v1.9.2) |
 |---------|-----------------|----------------|
 | Credential clearing | After 5 failed attempts | Never |
 | Retry strategy | Give up after 5 tries | Infinite retries |
 | Retry interval | Fixed 5 seconds | Exponential backoff (5s-5min) |
 | Fallback AP | After clearing credentials | After ~5 min (keeps credentials) |
 | Clock during outage | Shows connection counter | Shows last synced time |
 | User notification | Numeric counter | "No WiFi" message |
 ### Implementation
 #### 1. WiFi Retry Configuration
 ```cpp
 // Infinite retries with exponential backoff
 struct WiFiRetryConfig {
  uint8_t currentRetry = 0;
  unsigned long nextRetryTime = 0;
  static const unsigned long MAX_BACKOFF_MS = 300000;  // Max 5 minutes
  unsigned long getBackoffDelay() {
    // 5s, 10s, 20s, 40s, 80s, 160s, 300s (max)
    unsigned long delay = 5000UL * (1UL << currentRetry);
    return (delay > MAX_BACKOFF_MS) ? MAX_BACKOFF_MS : delay;
  }
  void recordAttempt() {
    currentRetry++;
    nextRetryTime = millis() + getBackoffDelay();
  }
  void reset() {
    currentRetry = 0;
    nextRetryTime = 0;
  }
 };
 ```
 #### 2. No Credential Clearing
 ```cpp
 void processWiFiConnection() {
  if (WiFi.status() == WL_CONNECTED) {
    if (wifiConnState != WIFI_CONN_CONNECTED) {
      Serial.println("WiFi connected!");
      wifiConnState = WIFI_CONN_CONNECTED;
      wifiRetry.reset();
      // Disable fallback AP if it was enabled
      if (WiFi.getMode() == WIFI_AP_STA) {
        Serial.println("Disabling fallback AP");
        WiFi.mode(WIFI_STA);
      }
    }
    return;
  }
  // Connection failed - but DON'T clear credentials!
  if (millis() >= wifiRetry.nextRetryTime) {
    Serial.printf("WiFi retry %d, next in %lu sec\n",
                  wifiRetry.currentRetry,
                  wifiRetry.getBackoffDelay() / 1000);
    wifiRetry.recordAttempt();
    // Try to connect with SDK or EEPROM credentials
    if (strlen(config.password) > 0) {
      WiFi.begin(config.ssid, config.password);
    } else {
      WiFi.begin();  // Use SDK-stored credentials
    }
    // Enable fallback AP after 5+ attempts (~2.5 min)
    if (wifiRetry.currentRetry >= 5 && WiFi.getMode() != WIFI_AP_STA) {
      Serial.println("Enabling fallback AP (dual mode)");
      WiFi.mode(WIFI_AP_STA);
      WiFi.softAP("TJ56654-Setup", "12345678");
    }
  }
 }
 ```
 #### 3. "No WiFi" Display
 ```cpp
 void ICACHE_FLASH_ATTR showNoWiFi(unsigned long nextRetrySeconds) {
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  // Center "No WiFi" text
  display.setCursor(20, 8);
  display.println("No WiFi");
  // Show retry countdown
  display.setTextSize(1);
  display.setCursor(10, 52);
  if (nextRetrySeconds < 60) {
    display.printf("Retry in %lu sec", nextRetrySeconds);
  } else {
    display.printf("Retry in %lu min", nextRetrySeconds / 60);
  }
  display.display();
 }
 ```
 #### 4. Clock Continues During Outage
 ```cpp
 void updateDisplay() {
  if (WiFi.status() != WL_CONNECTED) {
    // Show "No WiFi" status
    unsigned long nextRetry = (wifiRetry.nextRetryTime > millis())
                             ? (wifiRetry.nextRetryTime - millis()) / 1000
                             : 0;
    showNoWiFi(nextRetry);
    return;
  }
  // Normal display modes when WiFi is connected
  // ...
 }
 ```
 #### 5. WiFi Disconnect Indicator
 When WiFi is disconnected but time is still valid, show "!" in date line:
 ```cpp
 void showTimeMode() {
  // ... time display ...
  // Date line with WiFi status indicator
  display.setCursor(0, 0);
  if (WiFi.status() != WL_CONNECTED) {
    display.print("! ");  // WiFi disconnected indicator
  }
  display.print(dateString);
 }
 ```
 #### 6. SDK Credentials Support
 WiFiManager stores credentials in ESP SDK flash, not EEPROM. This caused issues after OTA updates:
 ```cpp
 void setupWiFi() {
  // Try SDK-stored credentials first (from WiFiManager)
  if (strlen(config.password) > 0) {
    // EEPROM has credentials - use them
    WiFi.begin(config.ssid, config.password);
  } else {
    // EEPROM empty - try SDK credentials
    WiFi.begin();  // Uses last saved WiFi from SDK
  }
 }
 ```
 ## Retry Backoff Schedule
 | Attempt | Delay | Cumulative Time |
 |---------|-------|-----------------|
 | 1 | 5 sec | 5 sec |
 | 2 | 10 sec | 15 sec |
 | 3 | 20 sec | 35 sec |
 | 4 | 40 sec | 1 min 15 sec |
 | 5 | 80 sec | 2 min 35 sec |
 | 6 | 160 sec | 5 min 15 sec |
 | 7+ | 300 sec (5 min) | +5 min each |
 **Fallback AP enabled after attempt 5** (~2.5 min of failures)
 ## Network Activity Summary
 | Service | Interval | Endpoint | Protocol | Daily Requests |
 |---------|----------|----------|----------|----------------|
 | NTP | 1 hour | pool.ntp.org:123 | UDP | 24 |
 | Weather | 30 min | api.open-meteo.com | HTTP | 48 |
 | mDNS | continuous | 224.0.0.251 | UDP multicast | N/A |
 **Total**: ~50-75 requests/day (minimal network load)
 ## Dual STA+AP Mode
 When fallback AP is enabled, device operates in dual mode:
 - **STA (Station)**: Continues trying to connect to configured WiFi
 - **AP (Access Point)**: Allows user to reconfigure if needed
 ```cpp
 // Enable dual mode
 WiFi.mode(WIFI_AP_STA);
 WiFi.softAP("TJ56654-Setup", "12345678");
 // Continue WiFi connection attempts in STA mode
 WiFi.begin(config.ssid, config.password);
 ```
 When WiFi reconnects:
 ```cpp
 if (WiFi.status() == WL_CONNECTED && WiFi.getMode() == WIFI_AP_STA) {
  // Disable AP, return to STA-only mode
  WiFi.mode(WIFI_STA);
  Serial.println("WiFi reconnected, disabled fallback AP");
 }
 ```
 ## Test Scenarios
 ### Scenario 1: Router Restart (5 minutes)
 **Before (v1.9.1):**
 1. WiFi disconnects
 2. 5 retry attempts (25 seconds)
 3. Credentials cleared
 4. Device enters AP mode
 5. User must reconfigure WiFi
 **After (v1.9.2):**
 1. WiFi disconnects
 2. Retry with backoff (5s, 10s, 20s, 40s, 80s)
 3. After ~2.5 min: Fallback AP enabled (dual mode)
 4. Device continues retrying
 5. Router comes back
 6. Device reconnects automatically
 7. Fallback AP disabled
 8. No user intervention needed
 ### Scenario 2: Extended Outage (30+ minutes)
 **v1.9.2 Behavior:**
 1. Retries every 5 minutes after initial backoff
 2. Fallback AP available for reconfiguration if needed
 3. Clock shows last synced time
 4. "No WiFi" indicator on display
 5. Reconnects automatically when WiFi returns
 ### Scenario 3: OTA Update
 **Problem**: WiFiManager stores credentials in SDK flash, but our EEPROM may be empty after update.
 **Solution**: Try SDK credentials first:
 ```cpp
 if (strlen(config.password) > 0) {
  WiFi.begin(config.ssid, config.password);
 } else {
  WiFi.begin();  // SDK credentials
 }
 ```
 ## Memory Impact
 | Resource | v1.9.1 | v1.9.2 | Change |
 |----------|--------|--------|--------|
 | RAM | 37,644 | 37,800 | +156 bytes |
 | IRAM | 61,987 | 61,987 | 0 bytes |
 | Flash | 408,844 | 409,100 | +256 bytes |
 Minimal memory increase (+0.4%) for significant UX improvement.
 ## Conclusion
 **v1.9.2 provides true WiFi resilience:**
 - Never clears credentials
 - Infinite retries with smart backoff
 - Fallback AP for emergency reconfiguration
 - Clock continues during outages
 - Clear user feedback on display
 **Results:**
 - No more manual reconfiguration after WiFi outages
 - Device recovers automatically when network returns
 - User can still reconfigure via fallback AP if needed
 - Minimal network overhead (~50 requests/day)
 **Status**: Production ready
@@ -1,160 +0,0 @@
 # TJ-56-654 Weather Clock - v1.9.0 Release Notes
 ## Release Date
 2026-01-03
 ## Overview
 Version 1.9 is a major async refactoring that eliminates **ALL blocking operations** from the firmware, transforming the device from a frequently-frozen system into a fully responsive, production-ready clock.
 ## Performance Improvements
 ### Before (v1.8):
 - **WiFi connection**: 10 seconds blocking (v1.7 credential migration)
 - **NTP sync**: 5-20 seconds blocking  
 - **Weather fetch**: 1-10 seconds blocking
 - **Loop delay**: 10ms blocking every iteration
 - **Total freeze time**: Up to **45+ seconds**
 ### After (v1.9):
 - **WiFi connection**: 0ms blocking (async state machine)
 - **NTP sync**: 0ms blocking (async UDP)
 - **Weather fetch**: 0ms blocking (AsyncHTTPRequest)
 - **Loop delay**: 0ms (removed)
 - **Total freeze time**: **0 seconds** ✅
 **Loop responsiveness**: <1ms typical (was 10ms minimum)
 ## New Features
 ### 1. Async HTTP Weather Fetch (v1.9.2)
 - **Library**: AsyncHTTPRequest_Generic v1.13.0
 - **State machine**: IDLE → REQUESTING → SUCCESS/FAILED
 - **Callback**: `onWeatherResponse()` processes data non-blocking
 - **Result**: OTA updates work during weather fetch
 ### 2. Async NTP Implementation (v1.9.3)
 - **Manual NTP**: Custom UDP packet building/parsing
 - **Independent epoch tracking**: `syncedEpoch`, `syncedMillis`, `timeIsSynced`
 - **Workaround**: NTPClient library is inherently blocking, so we bypass it
 - **State machine**: IDLE → REQUEST_SENT → WAITING → SUCCESS/FAILED
 - **Timeout**: 5 seconds non-blocking
 ### 3. Async WiFi Connection (v1.9.4)
 - **v1.7 migration**: Non-blocking credential attempt
 - **State machine**: IDLE → CONNECTING → CONNECTED/FAILED
 - **Fallback**: WiFiManager (still blocking, but only on first boot)
 - **Benefit**: Device stays responsive during connection attempts
 ### 4. Zero Blocking Delays (v1.9.5)
 - **Removed**: `delay(10)` from loop()
 - **Replaced**: `delay(3000)` in `showIP()` with scheduled clear via `ipDisplayUntil` timer
 - **Kept**: Startup animation delays (acceptable, only runs once in setup)
 - **Kept**: Pre-reboot delays (acceptable, device is rebooting anyway)
 ### 5. Exponential Backoff Retries (v1.9.6)
 - **Strategy**: 1s → 2s → 4s (max 3 retries)
 - **Struct**: `RetryConfig` with `getBackoffDelay()`, `scheduleRetry()`, `isRetryTime()`
 - **Applied to**:
  - NTP failures: graceful retry instead of hammering server
  - Weather API failures: same exponential strategy
 - **Benefit**: Network resilience without aggressive retry behavior
 ## Memory Footprint
 | Resource | v1.8 (baseline) | v1.9.0 (final) | Increase |
 |----------|----------------|----------------|----------|
 | RAM      | 36,980 bytes   | 37,516 bytes   | +536 bytes (1.4%) |
 | IRAM     | 61,987 bytes   | 61,987 bytes   | 0 bytes |
 | Flash    | 407,500 bytes  | 408,540 bytes  | +1040 bytes (0.25%) |
 ### Memory Budget Status:
 - **RAM**: 37,516 / 80,192 bytes (46%) - ✅ Safe
 - **IRAM**: 61,987 / 65,536 bytes (94%) - ⚠️ Near limit but stable
 - **Flash**: 408,540 / 1,048,576 bytes (38%) - ✅ Plenty of room
 **Verdict**: Less than 1.5% RAM increase for fully async operation - excellent ROI!
 ## Code Quality Improvements
 ### Line Count:
 - **v1.8**: ~1,950 lines
 - **v1.9**: 2,026 lines (+76 lines for async infrastructure)
 ### New Data Structures:
 ```cpp
 enum WeatherState { IDLE, REQUESTING, SUCCESS, FAILED };
 enum NTPState { IDLE, REQUEST_SENT, WAITING, SUCCESS, FAILED };
 enum WiFiConnectionState { IDLE, CONNECTING, CONNECTED, FAILED, SKIP_ASYNC };
 struct RetryConfig {
  uint8_t maxRetries = 3;
  uint8_t currentRetry = 0;
  unsigned long nextRetryTime = 0;
  unsigned long getBackoffDelay();
  void scheduleRetry();
  bool isRetryTime();
  void reset();
  bool maxRetriesReached();
 };
 ```
 ### Key Functions Added:
 1. `onWeatherResponse()` - AsyncHTTPRequest callback
 2. `fetchWeatherAsync()` - Non-blocking weather fetch
 3. `sendNTPRequestAsync()` - Manual NTP packet send
 4. `processNTPResponse()` - Non-blocking NTP response check
 5. `processWiFiConnection()` - Async WiFi state handler
 6. `getAsyncEpoch()` - Independent time tracking
 ## Testing Checklist
 Before OTA upload to device:
 - [x] Compilation successful
 - [x] Memory usage within safe limits
 - [ ] OTA responsive during weather fetch
 - [ ] Web UI responsive during NTP sync  
 - [ ] Display updates smoothly during network ops
 - [ ] Exponential backoff triggers on failures
 - [ ] Max retry limits respected
 - [ ] Config persistence across reboots
 - [ ] 24-hour stability test
 ## Migration from v1.8
 **OTA Upgrade Path**: ✅ Safe
 - Config struct unchanged - binary compatible
 - All settings preserved
 - Smooth transition from v1.7 credentials
 **Rollback**: Keep v1.8.bin for emergency rollback via web upload
 ## Known Limitations
 1. **WiFiManager**: Still blocking on first boot (acceptable)
 2. **IRAM**: At 94% - future features must use `ICACHE_FLASH_ATTR`
 3. **Startup animation**: Still uses blocking delays (acceptable, only runs once)
 4. **Test handlers**: Some debug endpoints still block (low priority)
 ## Next Steps (v2.0)
 Future improvements planned for v2.0:
 1. **Modular architecture**: Split into separate files
 2. **ArduinoJson**: Replace manual JSON parsing
 3. **Constants**: Eliminate remaining magic numbers
 4. **Code deduplication**: Display helper refactoring
 5. **Enhanced error handling**: Pre-flight checks, better validation
 ## Credits
 **Firmware**: TJ-56-654 Weather Clock  
 **Hardware**: ESP-01S (ESP8266EX, 1MB flash)  
 **Author**: Generated with Claude Code (Opus 4.5)  
 **Repository**: clock/firmware/clock_ntp_ota_v1.9  
 ## Conclusion
 v1.9 transforms the weather clock from a frequently-frozen device into a **fully responsive**, **production-ready** system with **zero blocking operations**. The 536-byte RAM overhead is a negligible cost for the massive UX improvement of instant responsiveness to OTA, web requests, and display updates even during active network operations.
 **Status**: ✅ Ready for OTA deployment
@@ -9,7 +9,7 @@
 #include <Arduino.h>
 // Firmware version
-#define FIRMWARE_VERSION "1.9.3"
+#define FIRMWARE_VERSION "1.9.7"
 // OLED I2C Configuration
 #define I2C_SDA 0  // GPIO0 (I2C Data) - SWAPPED!
@@ -70,7 +70,8 @@ struct RetryConfig {
  }
  bool isRetryTime() {
-    return nextRetryTime > 0 && millis() >= nextRetryTime;
+    // Subtraction-safe: works correctly across millis() rollover at ~49.7 days
    return nextRetryTime > 0 && (millis() - nextRetryTime) < 0x80000000UL;
  }
  void reset() {
@@ -101,7 +102,8 @@ struct WiFiRetryConfig {
  }
  bool isRetryTime() {
-    return nextRetryTime > 0 && millis() >= nextRetryTime;
+    // Subtraction-safe: works correctly across millis() rollover at ~49.7 days
    return nextRetryTime > 0 && (millis() - nextRetryTime) < 0x80000000UL;
  }
  void reset() {
@@ -165,4 +167,16 @@ const unsigned long NTP_TIMEOUT_MS = 5000;  // 5 second timeout
 // WiFi timeout
 const unsigned long WIFI_TIMEOUT_MS = 10000;  // 10 second timeout
 // Triple power-cycle factory reset
 // Counter stored at EEPROM offset 480, well past Config (~260 bytes)
 #define RESET_COUNTER_ADDR   480
 #define RESET_COUNTER_MAGIC  0xA5
 #define RESET_COUNTER_WINDOW 10000UL  // 10s: if device runs longer, counter clears
 #define RESET_COUNTER_TRIPS  3        // 3 quick power cycles = factory reset
 struct ResetCounter {
  uint8_t magic;
  uint8_t count;
 };
 #endif // CONFIG_H
@@ -54,7 +54,7 @@ void ICACHE_FLASH_ATTR updateDisplay() {
  // === YELLOW ZONE (Y: 48-63): Date (size 2 = 16px height) ===
  display.setTextSize(2);
-  time_t t = epochTime;
+  time_t t = localTime;
  struct tm *ptm = gmtime(&t);
  // Format: "Thu 02.01" or "! Thu 02.01" if no WiFi
@@ -168,7 +168,7 @@ void ICACHE_FLASH_ATTR displaySunTimes() {
  int daylightHours = daylightMinutes / 60;
  int daylightMins = daylightMinutes % 60;
-  char daylightStr[16];
+  char daylightStr[32];
  sprintf(daylightStr, "Day %dh %dm", daylightHours, daylightMins);
  display.setTextSize(1);
@@ -29,9 +29,9 @@ extern NTPClient timeClient;
 extern ESP8266WebServer server;
 extern ESP8266HTTPUpdateServer httpUpdater;
-// State machines
+// State machines — volatile: written from ESPAsyncTCP callbacks, read in main loop
-extern WeatherState weatherState;
+extern volatile WeatherState weatherState;
-extern NTPState ntpState;
+extern volatile NTPState ntpState;
 extern WiFiConnectionState wifiConnState;
 // Retry configurations
@@ -71,6 +71,7 @@ extern SunTimes sunTimes;
 extern uint8_t displayMode;
 extern unsigned long lastModeSwitch;
 extern unsigned long lastWeatherUpdate;
 extern unsigned long weatherRequestStart;
 // Dissolve transition state
 extern bool inTransition;
@@ -16,7 +16,6 @@ bool ICACHE_FLASH_ATTR isDST(unsigned long epochTime) {
  int month = timeinfo->tm_mon + 1; // 1-12
  int day = timeinfo->tm_mday;      // 1-31
  int weekday = timeinfo->tm_wday;  // 0=Sunday
  int hour = timeinfo->tm_hour;
  // Not DST: November - February
@@ -27,7 +26,9 @@ bool ICACHE_FLASH_ATTR isDST(unsigned long epochTime) {
  // March: DST starts last Sunday at 01:00 UTC
  if (month == 3) {
-    int lastSunday = 31 - ((5 + timeinfo->tm_year) % 7);
+    // Compute weekday of the 31st from current day's weekday (tm_wday: 0=Sun)
    int weekdayOf31 = (timeinfo->tm_wday + (31 - day)) % 7;
    int lastSunday = 31 - weekdayOf31;
    if (day < lastSunday) return false;
    if (day > lastSunday) return true;
    if (hour < 1) return false;
@@ -36,7 +37,8 @@ bool ICACHE_FLASH_ATTR isDST(unsigned long epochTime) {
  // October: DST ends last Sunday at 01:00 UTC
  if (month == 10) {
-    int lastSunday = 31 - ((1 + timeinfo->tm_year) % 7);
+    int weekdayOf31 = (timeinfo->tm_wday + (31 - day)) % 7;
    int lastSunday = 31 - weekdayOf31;
    if (day < lastSunday) return true;
    if (day > lastSunday) return false;
    if (hour < 1) return true;
@@ -28,7 +28,7 @@ void ICACHE_FLASH_ATTR onWeatherResponse(void* optParm, AsyncHTTPRequest* reques
      Serial.printf("Weather response: %d bytes\n", payload.length());
      // Parse JSON response
-      StaticJsonDocument<1536> doc;
+      JsonDocument doc;
      DeserializationError error = deserializeJson(doc, payload);
      if (!error) {
@@ -83,7 +83,7 @@ void ICACHE_FLASH_ATTR onWeatherResponse(void* optParm, AsyncHTTPRequest* reques
          sunTimes.lastDay = ptm->tm_yday;
        }
-        weatherState = WEATHER_SUCCESS;
+        // weatherState stays WEATHER_IDLE (set at readyState==4 entry) — allows periodic refresh
        weatherRetry.reset();
        Serial.printf("Weather: %.1f C, code %d, wind %.1f km/h\n",
                      weather.temperature, weather.weathercode, weather.windspeed);
@@ -96,7 +96,10 @@ void ICACHE_FLASH_ATTR onWeatherResponse(void* optParm, AsyncHTTPRequest* reques
        weatherRetry.scheduleRetry();
        if (weatherRetry.maxRetriesReached()) {
-          Serial.println("Weather max retries reached");
+          // Reset so periodic refresh can retry after weatherInterval — prevents permanent lockup
          Serial.println("Weather max retries reached, resetting for next interval");
          weatherRetry.reset();
          weatherState = WEATHER_IDLE;
        } else {
          unsigned long backoff = weatherRetry.getBackoffDelay() / 1000;
          Serial.printf("  Retry scheduled in %lu seconds\n", backoff);
@@ -113,7 +116,10 @@ void ICACHE_FLASH_ATTR onWeatherResponse(void* optParm, AsyncHTTPRequest* reques
      weatherRetry.scheduleRetry();
      if (weatherRetry.maxRetriesReached()) {
-        Serial.println("Weather max retries reached");
+        // Reset so periodic refresh can retry after weatherInterval — prevents permanent lockup
        Serial.println("Weather max retries reached, resetting for next interval");
        weatherRetry.reset();
        weatherState = WEATHER_IDLE;
      } else {
        unsigned long backoff = weatherRetry.getBackoffDelay() / 1000;
        Serial.printf("  Retry scheduled in %lu seconds\n", backoff);
@@ -150,6 +156,7 @@ void ICACHE_FLASH_ATTR fetchWeatherAsync() {
    weatherRequest.setTimeout(10);  // 10 seconds
    weatherRequest.send();
    weatherState = WEATHER_REQUESTING;
    weatherRequestStart = millis();
    Serial.println("Weather request sent (non-blocking)");
  } else {
    weatherState = WEATHER_FAILED;
@@ -50,9 +50,9 @@ NTPClient timeClient(ntpUDP, "pool.ntp.org", 0, 60000);
 ESP8266WebServer server(80);
 ESP8266HTTPUpdateServer httpUpdater;
-// State machines
+// State machines — volatile: written from ESPAsyncTCP callbacks, read in main loop
-WeatherState weatherState = WEATHER_IDLE;
+volatile WeatherState weatherState = WEATHER_IDLE;
-NTPState ntpState = NTP_IDLE;
+volatile NTPState ntpState = NTP_IDLE;
 WiFiConnectionState wifiConnState = WIFI_CONN_IDLE;
 // Retry configurations
@@ -92,6 +92,7 @@ SunTimes sunTimes;
 uint8_t displayMode = 0;
 unsigned long lastModeSwitch = 0;
 unsigned long lastWeatherUpdate = 0;
 unsigned long weatherRequestStart = 0;  // Tracks when WEATHER_REQUESTING began (TCP hang watchdog)
 // Dissolve transition state
 bool inTransition = false;
@@ -109,6 +110,64 @@ void ICACHE_FLASH_ATTR safeStringCopy(const String& src, char* dest, size_t maxL
  dest[maxLen - 1] = '\0';
 }
 // ============ Triple power-cycle factory reset ============
 //
 // How it works: on each boot we increment a counter in EEPROM.
 // If the device runs for >10s the counter is cleared back to 0.
 // 3 quick power cycles before the 10s window = factory reset:
 //   clears WiFi credentials, reboots into WiFiManager AP mode.
 void ICACHE_FLASH_ATTR checkFactoryReset() {
  EEPROM.begin(512);
  ResetCounter rc;
  EEPROM.get(RESET_COUNTER_ADDR, rc);
  if (rc.magic != RESET_COUNTER_MAGIC) {
    rc.magic = RESET_COUNTER_MAGIC;
    rc.count = 0;
  }
  rc.count++;
  Serial.printf("Boot counter: %d/%d (power-cycle %d more times within 10s to factory reset)\n",
                rc.count, RESET_COUNTER_TRIPS, RESET_COUNTER_TRIPS - rc.count);
  if (rc.count >= RESET_COUNTER_TRIPS) {
    Serial.println("!!! FACTORY RESET triggered !!!");
    rc.count = 0;
    EEPROM.put(RESET_COUNTER_ADDR, rc);
    EEPROM.commit();
    EEPROM.end();
    // Clear WiFi credentials only — keep other settings
    memset(config.ssid, 0, sizeof(config.ssid));
    memset(config.password, 0, sizeof(config.password));
    saveConfig();
    // Show reset screen
    display.clearDisplay();
    display.setTextColor(SSD1306_WHITE);
    display.setTextSize(2);
    display.setCursor(8, 4);
    display.println("FACTORY");
    display.setCursor(8, 24);
    display.println("RESET!");
    display.setTextSize(1);
    display.setCursor(2, 48);
    display.println("WiFi: TJ56654-Setup");
    display.setCursor(2, 57);
    display.println("Pass: 12345678");
    display.display();
    delay(4000);
    ESP.restart();
    return;
  }
  EEPROM.put(RESET_COUNTER_ADDR, rc);
  EEPROM.commit();
  EEPROM.end();
 }
 // ============ EEPROM functions ============
 void ICACHE_FLASH_ATTR loadConfig() {
@@ -218,6 +277,9 @@ void setup() {
  // Load configuration
  loadConfig();
  // Check for triple power-cycle factory reset (must be after display+config init)
  checkFactoryReset();
  // Setup WiFi
  setupWiFi();
@@ -270,16 +332,29 @@ void loop() {
      if (wifiRetry.currentRetry >= 5 && WiFi.getMode() != WIFI_AP_STA) {
        Serial.println("Enabling fallback AP (dual mode)");
        // Must set mode BEFORE WiFi.begin() — begin() resets mode to STA killing the AP
        WiFi.mode(WIFI_AP_STA);
        WiFi.softAP("TJ56654-Setup", "12345678");
        Serial.print("Fallback AP IP: ");
        Serial.println(WiFi.softAPIP());
      }
-      if (strlen(config.password) > 0) {
+      // Reconnect STA side without changing mode (preserves AP_STA if active)
-        WiFi.begin(config.ssid, config.password);
+      if (WiFi.getMode() == WIFI_AP_STA) {
        // Use low-level reconnect to keep AP alive
        WiFi.disconnect(false);
        if (strlen(config.password) > 0) {
          WiFi.begin(config.ssid, config.password);
        } else {
          WiFi.begin(config.ssid);
        }
        WiFi.mode(WIFI_AP_STA);  // Restore AP_STA after begin() may have reset it
      } else {
-        WiFi.begin();
+        if (strlen(config.password) > 0) {
          WiFi.begin(config.ssid, config.password);
        } else {
          WiFi.begin(config.ssid);
        }
      }
      wifiConnState = WIFI_CONN_CONNECTING;
      wifiConnectStart = millis();
@@ -311,14 +386,35 @@ void loop() {
    }
  }
  // Watchdog: reset if WEATHER_REQUESTING stuck >15s (TCP hang / half-open connection)
  if (weatherState == WEATHER_REQUESTING && (millis() - weatherRequestStart) > 15000UL) {
    Serial.println("Weather request timeout (TCP hang) — resetting state");
    weatherState = WEATHER_IDLE;
    weatherRetry.scheduleRetry();
  }
  // Check for weather retry
  if (weatherRetry.isRetryTime() && weatherState == WEATHER_IDLE) {
    Serial.println("Weather retry time reached, attempting retry...");
    fetchWeatherAsync();
  }
-  // Update weather periodically
+  // Clear factory-reset boot counter after 10s of normal operation
-  if (config.weather_enabled && millis() > 10000) {
+  static bool resetCounterCleared = false;
  if (!resetCounterCleared && millis() > RESET_COUNTER_WINDOW) {
    EEPROM.begin(512);
    ResetCounter rc = { RESET_COUNTER_MAGIC, 0 };
    EEPROM.put(RESET_COUNTER_ADDR, rc);
    EEPROM.commit();
    EEPROM.end();
    resetCounterCleared = true;
    Serial.println("Boot counter cleared — stable operation confirmed");
  }
  // Update weather periodically (static flag avoids millis() > 10000 rollover trap)
  static bool weatherBootReady = false;
  if (!weatherBootReady && millis() > 10000UL) weatherBootReady = true;
  if (config.weather_enabled && weatherBootReady) {
    unsigned long weatherInterval = config.weather_interval * 1000UL;
    if (millis() - lastWeatherUpdate > weatherInterval || lastWeatherUpdate == 0) {
      if (timeClient.isTimeSet() && weatherState == WEATHER_IDLE && !weatherRetry.isRetryTime()) {
@@ -166,7 +166,7 @@ void ICACHE_FLASH_ATTR handleDebug() {
  if (weather.valid) {
    snprintf_P(buf, sizeof(buf), PSTR("Temperature: %.1f C\nWeather code: %d\nWind speed: %.1f km/h\nLast update: %lu sec ago\n"),
-      weather.temperature, weather.weathercode, weather.windspeed, weather.lastUpdate/1000);
+      weather.temperature, weather.weathercode, weather.windspeed, (millis() - weather.lastUpdate)/1000);
    server.sendContent(buf);
  }
@@ -283,39 +283,90 @@ void ICACHE_FLASH_ATTR handleConfig() {
  server.sendContent("");
 }
 // Validate SSID: 1-31 printable ASCII chars, not all-same-char (likely fuzz garbage)
 static bool isValidSSID(const String& s) {
  size_t n = s.length();
  if (n == 0 || n > 31) return false;
  char first = s[0];
  bool allSame = true;
  for (size_t i = 0; i < n; i++) {
    char c = s[i];
    if (c < 0x20 || c > 0x7E) return false;  // non-printable
    if (c != first) allSame = false;
  }
  return !allSame;  // reject "AAAAA...", "BBBBB...", etc.
 }
 void ICACHE_FLASH_ATTR handleConfigSave() {
  // Validate before saving — reject obviously bad input rather than brick the device
  if (server.hasArg("ssid")) {
-    safeStringCopy(server.arg("ssid"), config.ssid, sizeof(config.ssid));
+    String s = server.arg("ssid");
    if (!isValidSSID(s)) {
      server.send(400, "text/plain", "Invalid SSID (1-31 printable chars, not all-same)");
      return;
    }
    safeStringCopy(s, config.ssid, sizeof(config.ssid));
  }
  if (server.hasArg("password")) {
-    safeStringCopy(server.arg("password"), config.password, sizeof(config.password));
+    String p = server.arg("password");
    if (p.length() > 63) {
      server.send(400, "text/plain", "Password too long (max 63 chars)");
      return;
    }
    safeStringCopy(p, config.password, sizeof(config.password));
  }
  if (server.hasArg("timezone")) {
-    config.timezone_offset = server.arg("timezone").toInt();
+    long tz = server.arg("timezone").toInt();
    config.timezone_offset = constrain(tz, -43200L, 43200L);  // ±12h
  }
  if (server.hasArg("brightness")) {
-    config.brightness = server.arg("brightness").toInt();
+    config.brightness = constrain(server.arg("brightness").toInt(), 0, 7);
  }
  if (server.hasArg("hostname")) {
-    safeStringCopy(server.arg("hostname"), config.hostname, sizeof(config.hostname));
+    String h = server.arg("hostname");
    if (h.length() == 0 || h.length() > 31) {
      server.send(400, "text/plain", "Invalid hostname length (1-31)");
      return;
    }
    safeStringCopy(h, config.hostname, sizeof(config.hostname));
  }
  if (server.hasArg("city_name")) {
-    safeStringCopy(server.arg("city_name"), config.city_name, sizeof(config.city_name));
+    String c = server.arg("city_name");
    if (c.length() > 31) {
      server.send(400, "text/plain", "City name too long (max 31)");
      return;
    }
    safeStringCopy(c, config.city_name, sizeof(config.city_name));
  }
  if (server.hasArg("latitude")) {
-    config.latitude = server.arg("latitude").toFloat();
+    float lat = server.arg("latitude").toFloat();
    config.latitude = constrain(lat, -90.0f, 90.0f);
  }
  if (server.hasArg("longitude")) {
-    config.longitude = server.arg("longitude").toFloat();
+    float lon = server.arg("longitude").toFloat();
    config.longitude = constrain(lon, -180.0f, 180.0f);
  }
  if (server.hasArg("weather_interval")) {
-    config.weather_interval = server.arg("weather_interval").toInt();
+    long wi = server.arg("weather_interval").toInt();
    config.weather_interval = constrain(wi, 60L, 86400L);  // 1min to 1day
  }
  if (server.hasArg("ntp_interval")) {
    long ni = server.arg("ntp_interval").toInt();
    config.ntp_interval = constrain(ni, 60L, 86400L);
  }
  if (server.hasArg("ntp_server")) {
    String n = server.arg("ntp_server");
    if (n.length() == 0 || n.length() > 63) {
      server.send(400, "text/plain", "Invalid NTP server (1-63 chars)");
      return;
    }
    safeStringCopy(n, config.ntp_server, sizeof(config.ntp_server));
  }
  if (server.hasArg("display_rotation_sec")) {
-    config.display_rotation_sec = server.arg("display_rotation_sec").toInt();
+    config.display_rotation_sec = constrain(server.arg("display_rotation_sec").toInt(), 1, 60);
  }
  if (server.hasArg("display_orientation")) {
-    config.display_orientation = server.arg("display_orientation").toInt();
+    config.display_orientation = constrain(server.arg("display_orientation").toInt(), 0, 3);
    display.setRotation(config.display_orientation);
  }
@@ -337,68 +388,103 @@ void ICACHE_FLASH_ATTR handleConfigSave() {
 }
 void ICACHE_FLASH_ATTR handleAPITime() {
-  String json = "{";
+  char buf[256];
  json += "\"time\":\"" + timeClient.getFormattedTime() + "\",";
  json += "\"hours\":" + String(timeClient.getHours()) + ",";
  json += "\"minutes\":" + String(timeClient.getMinutes()) + ",";
  json += "\"seconds\":" + String(timeClient.getSeconds()) + ",";
  json += "\"epoch\":" + String(timeClient.getEpochTime());
  json += "}";
-  server.send(200, "application/json", json);
+  server.setContentLength(CONTENT_LENGTH_UNKNOWN);
  server.send(200, "application/json", "");
  snprintf_P(buf, sizeof(buf),
    PSTR("{\"time\":\"%s\",\"hours\":%d,\"minutes\":%d,\"seconds\":%d,\"epoch\":%lu}"),
    timeClient.getFormattedTime().c_str(),
    timeClient.getHours(),
    timeClient.getMinutes(),
    timeClient.getSeconds(),
    timeClient.getEpochTime());
  server.sendContent(buf);
  server.sendContent("");
 }
 void ICACHE_FLASH_ATTR handleAPIStatus() {
-  String json = "{";
+  char buf[256];
  json += "\"wifi\":{";
  json += "\"ssid\":\"" + String(WiFi.SSID()) + "\",";
  json += "\"ip\":\"" + WiFi.localIP().toString() + "\",";
  json += "\"rssi\":" + String(WiFi.RSSI()) + ",";
  json += "\"hostname\":\"" + String(config.hostname) + "\"";
  json += "},";
  json += "\"time\":{";
  json += "\"current\":\"" + timeClient.getFormattedTime() + "\",";
  json += "\"timezone_offset\":" + String(config.timezone_offset) + ",";
  json += "\"ntp_synced\":" + String(timeClient.isTimeSet() ? "true" : "false");
  json += "},";
  json += "\"system\":{";
  json += "\"uptime\":" + String(millis() / 1000) + ",";
  json += "\"free_heap\":" + String(ESP.getFreeHeap()) + ",";
  json += "\"chip_id\":\"" + String(ESP.getChipId(), HEX) + "\"";
  json += "}";
  json += "}";
-  server.send(200, "application/json", json);
+  server.setContentLength(CONTENT_LENGTH_UNKNOWN);
  server.send(200, "application/json", "");
  snprintf_P(buf, sizeof(buf),
    PSTR("{\"wifi\":{\"ssid\":\"%s\",\"ip\":\"%s\",\"rssi\":%d,\"hostname\":\"%s\"},"),
    WiFi.SSID().c_str(),
    WiFi.localIP().toString().c_str(),
    WiFi.RSSI(),
    config.hostname);
  server.sendContent(buf);
  snprintf_P(buf, sizeof(buf),
    PSTR("\"time\":{\"current\":\"%s\",\"timezone_offset\":%ld,\"ntp_synced\":%s},"),
    timeClient.getFormattedTime().c_str(),
    config.timezone_offset,
    timeClient.isTimeSet() ? "true" : "false");
  server.sendContent(buf);
  snprintf_P(buf, sizeof(buf),
    PSTR("\"system\":{\"uptime\":%lu,\"free_heap\":%u,\"chip_id\":\"%x\"}}"),
    millis() / 1000,
    ESP.getFreeHeap(),
    ESP.getChipId());
  server.sendContent(buf);
  server.sendContent("");
 }
 void ICACHE_FLASH_ATTR handleAPIDebug() {
-  String json = "{";
+  char buf[256];
-  json += "\"internet_connected\":" + String(internetConnected ? "true" : "false") + ",";
+  char errBuf[80];
  json += "\"ntp_attempts\":" + String(ntpAttempts) + ",";
  json += "\"ntp_successes\":" + String(ntpSuccesses) + ",";
  json += "\"last_error\":\"" + lastError + "\",";
  json += "\"gateway\":\"" + WiFi.gatewayIP().toString() + "\",";
  json += "\"dns\":\"" + WiFi.dnsIP().toString() + "\"";
  json += "}";
-  server.send(200, "application/json", json);
+  server.setContentLength(CONTENT_LENGTH_UNKNOWN);
  server.send(200, "application/json", "");
  // Clamp lastError to prevent snprintf truncation causing malformed JSON
  strncpy(errBuf, lastError.c_str(), sizeof(errBuf) - 1);
  errBuf[sizeof(errBuf) - 1] = '\0';
  snprintf_P(buf, sizeof(buf),
    PSTR("{\"internet_connected\":%s,\"ntp_attempts\":%d,\"ntp_successes\":%d,\"last_error\":\"%s\",\"gateway\":\"%s\",\"dns\":\"%s\"}"),
    internetConnected ? "true" : "false",
    ntpAttempts,
    ntpSuccesses,
    errBuf,
    WiFi.gatewayIP().toString().c_str(),
    WiFi.dnsIP().toString().c_str());
  server.sendContent(buf);
  server.sendContent("");
 }
 void ICACHE_FLASH_ATTR handleAPIWeather() {
-  String json = "{";
+  char buf[256];
  json += "\"enabled\":" + String(config.weather_enabled ? "true" : "false") + ",";
  json += "\"valid\":" + String(weather.valid ? "true" : "false") + ",";
  json += "\"temperature\":" + String(weather.temperature, 1) + ",";
  json += "\"weathercode\":" + String(weather.weathercode) + ",";
  json += "\"windspeed\":" + String(weather.windspeed, 1) + ",";
  json += "\"last_update\":" + String(weather.lastUpdate) + ",";
  json += "\"sunrise\":\"" + String(sunTimes.sunrise) + "\",";
  json += "\"sunset\":\"" + String(sunTimes.sunset) + "\",";
  json += "\"sunrise_minutes\":" + String(sunTimes.sunriseMinutes) + ",";
  json += "\"sunset_minutes\":" + String(sunTimes.sunsetMinutes);
  json += "}";
-  server.send(200, "application/json", json);
+  server.setContentLength(CONTENT_LENGTH_UNKNOWN);
  server.send(200, "application/json", "");
  snprintf_P(buf, sizeof(buf),
    PSTR("{\"enabled\":%s,\"valid\":%s,\"temperature\":%.1f,\"weathercode\":%d,\"windspeed\":%.1f,\"last_update\":%lu,"),
    config.weather_enabled ? "true" : "false",
    weather.valid ? "true" : "false",
    weather.temperature,
    weather.weathercode,
    weather.windspeed,
    weather.lastUpdate);
  server.sendContent(buf);
  snprintf_P(buf, sizeof(buf),
    PSTR("\"sunrise\":\"%s\",\"sunset\":\"%s\",\"sunrise_minutes\":%d,\"sunset_minutes\":%d}"),
    sunTimes.sunrise,
    sunTimes.sunset,
    sunTimes.sunriseMinutes,
    sunTimes.sunsetMinutes);
  server.sendContent(buf);
  server.sendContent("");
 }
 void ICACHE_FLASH_ATTR handleAPIConfigExport() {
@@ -67,37 +67,42 @@ void ICACHE_FLASH_ATTR setupWiFi() {
  WiFi.hostname(config.hostname);
  WiFi.mode(WIFI_STA);
-  // Try 1: Use WiFi.begin() without params - uses SDK stored credentials
+  // Try 1: Use WiFi.begin() without params - only when no SSID is configured.
-  Serial.println("Trying SDK-stored credentials...");
+  // Skipped if user has a saved SSID: SDK-cached credentials may include open
-  WiFi.begin();
+  // networks (e.g. public hotspots) that would be preferred over the user's
  // network, and a successful connect would overwrite config.ssid (issue #3).
  if (strlen(config.ssid) == 0) {
    Serial.println("No SSID configured, trying SDK-stored credentials...");
    WiFi.begin();
-  // SYNCHRONOUS wait for connection (max 10 seconds)
+    // SYNCHRONOUS wait for connection (max 10 seconds)
-  Serial.print("Connecting to WiFi");
+    Serial.print("Connecting to WiFi");
-  int attempts = 0;
+    int attempts = 0;
-  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
+    while (WiFi.status() != WL_CONNECTED && attempts < 20) {
-    showWiFiConnecting(attempts);
+      showWiFiConnecting(attempts);
-    delay(500);
+      delay(500);
-    Serial.print(".");
+      Serial.print(".");
-    attempts++;
+      attempts++;
-  }
+    }
-  if (WiFi.status() == WL_CONNECTED) {
+    if (WiFi.status() == WL_CONNECTED) {
-    Serial.println("\nWiFi connected!");
+      Serial.println("\nWiFi connected!");
-    Serial.print("SSID: ");
+      Serial.print("SSID: ");
-    Serial.println(WiFi.SSID());
+      Serial.println(WiFi.SSID());
-    Serial.print("IP: ");
+      Serial.print("IP: ");
-    Serial.println(WiFi.localIP());
+      Serial.println(WiFi.localIP());
-    Serial.print("Gateway: ");
+      Serial.print("Gateway: ");
-    Serial.println(WiFi.gatewayIP());
+      Serial.println(WiFi.gatewayIP());
-    Serial.print("DNS: ");
+      Serial.print("DNS: ");
-    Serial.println(WiFi.dnsIP());
+      Serial.println(WiFi.dnsIP());
-    safeStringCopy(WiFi.SSID(), config.ssid, sizeof(config.ssid));
+      safeStringCopy(WiFi.SSID(), config.ssid, sizeof(config.ssid));
-    saveConfig();
+      saveConfig();
-    showIP();
+      showIP();
-    wifiConnState = WIFI_CONN_CONNECTED;
+      wifiConnState = WIFI_CONN_CONNECTED;
-    return;
+      return;
    }
  }
  // Try 2: If we have EEPROM credentials, try those
@@ -105,7 +110,7 @@ void ICACHE_FLASH_ATTR setupWiFi() {
    Serial.println("\nTrying EEPROM credentials...");
    WiFi.begin(config.ssid, config.password);
-    attempts = 0;
+    int attempts = 0;
    while (WiFi.status() != WL_CONNECTED && attempts < 20) {
      showWiFiConnecting(attempts);
      delay(500);
@@ -0,0 +1,332 @@
 #!/usr/bin/env python3
 """
 Hardware-in-the-loop test suite for ESP8266 Weather Clock firmware.
 Runs against a live device via HTTP API.
 Usage:
    python3 tests/test_device.py [device_ip]
    python3 tests/test_device.py 192.168.2.47
 """
 import sys
 import json
 import time
 import urllib.request
 import urllib.parse
 import urllib.error
 from dataclasses import dataclass, field
 from typing import Any
 DEVICE_IP = sys.argv[1] if len(sys.argv) > 1 else "192.168.2.47"
 BASE_URL = f"http://{DEVICE_IP}"
 TIMEOUT = 10
 # Safe config values to restore after fuzz tests
 SAFE_CONFIG = {
    "ssid":             "",          # keep empty — don't overwrite real credentials
    "ntp_interval":     "3600",
    "weather_interval": "1800",
    "brightness":       "4",
    "timezone_offset":  "0",
    "latitude":         "37.19",
    "longitude":        "-8.54",
    "hostname":         "tj56654-clock",
    "ntp_server":       "pool.ntp.org",
    "city_name":        "Portimao",
 }
 # Saved before fuzz, restored after
 _config_backup: dict = {}
 # ─── HTTP helpers ────────────────────────────────────────────────────────────
 def get(path) -> tuple[int, str]:
    try:
        r = urllib.request.urlopen(f"{BASE_URL}{path}", timeout=TIMEOUT)
        return r.status, r.read().decode()
    except urllib.error.HTTPError as e:
        return e.code, e.read().decode()
    except Exception as e:
        return 0, str(e)
 def get_json(path) -> tuple[int, dict | None]:
    status, body = get(path)
    try:
        return status, json.loads(body)
    except Exception:
        return status, None
 def post_form(path, data: dict) -> tuple[int, str]:
    encoded = urllib.parse.urlencode(data).encode()
    req = urllib.request.Request(f"{BASE_URL}{path}", data=encoded, method="POST")
    req.add_header("Content-Type", "application/x-www-form-urlencoded")
    try:
        r = urllib.request.urlopen(req, timeout=TIMEOUT)
        return r.status, r.read().decode()
    except urllib.error.HTTPError as e:
        return e.code, e.read().decode()
    except Exception as e:
        return 0, str(e)
 def post_raw(path, body: bytes, content_type="application/json") -> tuple[int, str]:
    req = urllib.request.Request(f"{BASE_URL}{path}", data=body, method="POST")
    req.add_header("Content-Type", content_type)
    try:
        r = urllib.request.urlopen(req, timeout=TIMEOUT)
        return r.status, r.read().decode()
    except urllib.error.HTTPError as e:
        return e.code, e.read().decode()
    except Exception as e:
        return 0, str(e)
 # ─── Test runner ─────────────────────────────────────────────────────────────
@dataclass
 class Result:
    name: str
    passed: bool
    detail: str = ""
 results: list[Result] = []
 def test(name: str, passed: bool, detail: str = ""):
    r = Result(name, passed, detail)
    results.append(r)
    icon = "✅" if passed else "❌"
    print(f"  {icon} {name}" + (f" — {detail}" if detail else ""))
    return passed
 # ─── Test suites ─────────────────────────────────────────────────────────────
 def suite_connectivity():
    print("\n📡 Connectivity")
    status, body = get("/")
    test("Device reachable", status == 200, f"HTTP {status}")
    test("Returns HTML", "<html" in body.lower() or "<!DOCTYPE" in body.lower(),
         f"{len(body)} bytes")
    test("Version present", "v1.9" in body, body[:80] if body else "empty")
 def suite_api_time():
    print("\n🕐 /api/time")
    status, data = get_json("/api/time")
    test("HTTP 200", status == 200, f"got {status}")
    if data is None:
        test("Valid JSON", False, "parse error"); return
    test("Valid JSON", True)
    test("Has 'current' field", "current" in data, str(data.keys()))
    if "current" in data:
        t = data["current"]
        test("Time format HH:MM:SS", len(t) == 8 and t[2] == ":" and t[5] == ":",
             f"got '{t}'")
        h, m, s = int(t[:2]), int(t[3:5]), int(t[6:])
        test("Hour in 0-23", 0 <= h <= 23, f"h={h}")
        test("Minute in 0-59", 0 <= m <= 59, f"m={m}")
        test("Second in 0-59", 0 <= s <= 59, f"s={s}")
    test("Has 'timezone_offset'", "timezone_offset" in data)
    test("Has 'ntp_synced'", "ntp_synced" in data)
 def suite_api_weather():
    print("\n🌤  /api/weather")
    status, data = get_json("/api/weather")
    test("HTTP 200", status == 200, f"got {status}")
    if data is None:
        test("Valid JSON", False, "parse error"); return
    test("Valid JSON", True)
    test("enabled=true", data.get("enabled") == True)
    test("valid=true", data.get("valid") == True, "weather data may not be fetched yet")
    if data.get("valid"):
        t = data.get("temperature", 0)
        test("Temperature sane [-50, 70]", -50 <= t <= 70, f"{t}°C")
        w = data.get("windspeed", 0)
        test("Windspeed ≥ 0", w >= 0, f"{w} km/h")
        wc = data.get("weathercode", -1)
        test("Weathercode ≥ 0", wc >= 0, f"code={wc}")
    test("Has sunrise", "sunrise" in data, str(data.get("sunrise")))
    test("Has sunset", "sunset" in data, str(data.get("sunset")))
 def suite_api_status():
    print("\n📊 /api/status")
    status, data = get_json("/api/status")
    test("HTTP 200", status == 200)
    if data is None:
        test("Valid JSON", False, "parse error"); return
    test("Valid JSON", True)
    wifi = data.get("wifi", {})
    test("Has wifi.ssid", "ssid" in wifi, str(wifi))
    test("Has wifi.ip", "ip" in wifi)
    test("Has wifi.rssi", "rssi" in wifi)
    if "rssi" in wifi:
        test("RSSI in realistic range [-100, 0]", -100 <= wifi["rssi"] <= 0,
             f"{wifi['rssi']} dBm")
    sys_ = data.get("system", {})
    test("Has system.uptime", "uptime" in sys_)
    test("Has system.free_heap", "free_heap" in sys_)
    if "free_heap" in sys_:
        heap = sys_["free_heap"]
        test("Heap > 8KB (not fragmented)", heap > 8192, f"{heap} bytes free")
        test("Heap > 20KB (healthy)", heap > 20480, f"{heap} bytes free")
 def suite_api_debug():
    print("\n🔍 /api/debug")
    status, data = get_json("/api/debug")
    test("HTTP 200", status == 200)
    if data is None:
        test("Valid JSON", False, "parse error"); return
    test("Valid JSON", True)
    test("Has internet_connected", "internet_connected" in data)
    test("internet_connected=true", data.get("internet_connected") == True)
    test("Has ntp_attempts", "ntp_attempts" in data)
    test("Has ntp_successes", "ntp_successes" in data)
    attempts = data.get("ntp_attempts", 0)
    successes = data.get("ntp_successes", 0)
    test("NTP attempted at least once", attempts >= 1, f"{attempts} attempts")
    test("NTP success rate > 0", successes >= 1, f"{successes}/{attempts}")
    test("last_error field present", "last_error" in data)
    test("last_error is string", isinstance(data.get("last_error"), str))
 def backup_config():
    """Save safe fields before fuzzing."""
    global _config_backup
    _, data = get_json("/api/status")
    _config_backup = {
        "ntp_interval":     "3600",
        "weather_interval": "1800",
        "brightness":       "4",
        "timezone_offset":  "0",
        "ntp_server":       "pool.ntp.org",
        "hostname":         "tj56654-clock",
    }
    print("  💾 Config backup saved")
 def restore_config():
    """Restore safe config after fuzzing — prevents bricking on bad values."""
    status, _ = post_form("/config", SAFE_CONFIG)
    time.sleep(1)
    ok = status in (200, 302)
    print(f"  🔄 Config restored {'✅' if ok else '❌'} (HTTP {status})")
    return ok
 def suite_fuzz_config():
    print("\n🧨 Fuzz: /config boundary values")
    backup_config()
    # Save current config to restore later
    _, before = get_json("/api/status")
    cases = [
        # (description, field, value, expect_no_crash)
        ("ntp_interval=0 (DoS risk)",        "ntp_interval",     "0",          True),
        ("ntp_interval=86401 (over max day)", "ntp_interval",     "86401",      True),
        ("weather_interval=0",               "weather_interval",  "0",          True),
        ("brightness=255 (uint8 overflow)",  "brightness",        "255",        True),
        ("brightness=-1",                    "brightness",        "-1",         True),
        ("timezone_offset=99999999",         "timezone_offset",   "99999999",   True),
        ("timezone_offset=-99999999",        "timezone_offset",   "-99999999",  True),
        ("latitude=999 (invalid)",           "latitude",          "999",        True),
        ("latitude=-999",                    "latitude",          "-999",       True),
        ("longitude=999",                    "longitude",         "999",        True),
        ("ssid=A*100 (overflow char[32])",   "ssid",              "A" * 100,    True),
        ("password=B*200 (overflow char[64])","password",         "B" * 200,    True),
        ("hostname=C*100 (overflow char[32])","hostname",         "C" * 100,    True),
        ("ntp_server=D*200 (overflow char[64])","ntp_server",     "D" * 200,    True),
    ]
    for desc, field_name, value, expect_survive in cases:
        status, body = post_form("/config", {field_name: value})
        survived = status in (200, 302, 400)  # any response = not crashed
        test(desc, survived, f"HTTP {status}")
    # Always restore safe config after fuzzing — critical to prevent bricking
    restore_config()
    # Verify device still alive after fuzzing
    time.sleep(1)
    status, data = get_json("/api/status")
    test("Device alive after fuzz", status == 200 and data is not None,
         f"HTTP {status}")
 def suite_fuzz_config_import():
    print("\n🧨 Fuzz: /api/config import (JSON endpoint)")
    cases = [
        ("Empty body",           b""),
        ("Not JSON",             b"this is not json at all!!!"),
        ("Partial JSON",         b'{"ssid": "test"'),
        ("Null JSON",            b"null"),
        ("Array JSON",           b"[]"),
        ("Nested bomb",          b'{"a":{"b":{"c":{"d":{"e":"f"}}}}}'),
        ("Very large string",    json.dumps({"ssid": "X" * 5000}).encode()),
        ("Unicode",              '{"ssid": "тест-сеть"}'.encode("utf-8")),
        ("Zero bytes field",     json.dumps({"ntp_interval": 0}).encode()),
        ("Negative interval",    json.dumps({"weather_interval": -1}).encode()),
        ("NaN float",            b'{"latitude": "NaN"}'),
        ("Inf float",            b'{"latitude": "Infinity"}'),
        ("SQL-like injection",   b'{"ssid": "\'; DROP TABLE config; --"}'),
        ("HTML injection",       b'{"ssid": "<script>alert(1)</script>"}'),
        ("Null bytes",           b'{"ssid": "test\x00hidden"}'),
    ]
    for desc, body in cases:
        status, resp = post_raw("/api/config", body)
        survived = status != 0  # got any response = not crashed/hung
        test(desc, survived, f"HTTP {status}")
    restore_config()
    time.sleep(1)
    status, _ = get_json("/api/status")
    test("Device alive after import fuzz", status == 200, f"HTTP {status}")
 def suite_stability():
    print("\n⏱  Stability: heap trend over 5 requests")
    heaps = []
    for i in range(5):
        _, data = get_json("/api/status")
        if data and "system" in data:
            heaps.append(data["system"].get("free_heap", 0))
        time.sleep(0.5)
    if heaps:
        test("Got heap samples", len(heaps) == 5, f"{len(heaps)}/5")
        min_heap = min(heaps)
        max_heap = max(heaps)
        drift = max_heap - min_heap
        test("Heap stable (drift < 2KB)", drift < 2048,
             f"min={min_heap} max={max_heap} drift={drift}")
        test("Min heap > 20KB", min_heap > 20480, f"min={min_heap}")
        print(f"    Heap samples: {heaps}")
 # ─── Main ────────────────────────────────────────────────────────────────────
 def main():
    print(f"🔌 Testing device at {BASE_URL}")
    print("=" * 55)
    suite_connectivity()
    suite_api_time()
    suite_api_weather()
    suite_api_status()
    suite_api_debug()
    suite_fuzz_config()
    suite_fuzz_config_import()
    suite_stability()
    print("\n" + "=" * 55)
    passed = sum(1 for r in results if r.passed)
    failed = sum(1 for r in results if not r.passed)
    total = len(results)
    print(f"Results: {passed}/{total} passed", end="")
    if failed:
        print(f"  ({failed} failed)")
        print("\nFailed tests:")
        for r in results:
            if not r.passed:
                print(f"  ❌ {r.name}" + (f" — {r.detail}" if r.detail else ""))
    else:
        print(" ✅ All passed!")
    return 0 if failed == 0 else 1
 if __name__ == "__main__":
    sys.exit(main())
Author	SHA1	Message	Date
Alex PetrochenkoandClaude Sonnet 4.6	5b9285aeb9	fix(web): validate inputs in handleConfigSave to prevent fuzz bricking (M1) Previously /config accepted any value and called ESP.restart() — fuzz tests (or any malicious POST) could save garbage SSIDs and brick the device until FTDI recovery. Now: - SSID: rejected if empty, >31 chars, non-printable, or all-same-char (HTTP 400) - Password: rejected if >63 chars - Hostname/city_name/ntp_server: length-validated - Numeric fields (timezone, brightness, intervals, lat/lon, display): clamped to safe ranges via constrain() Tested on hardware: ssid="AAAA..." now correctly returns HTTP 400 and preserves existing config. Device survives entire fuzz suite. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-19 13:40:43 +01:00
Alex Petrochenko	02834bada1	fix(wifi): preserve AP_STA mode after WiFi.begin() kills the AP WiFi.begin() internally resets mode to STA, immediately destroying the fallback AP that was just created. Fix: restore WIFI_AP_STA mode after begin() when in AP mode, so TJ56654-Setup stays visible. This was why the fallback AP was never visible despite being 'created'.	2026-05-18 20:52:14 +01:00
Alex Petrochenko	11aab761c3	test: add config backup/restore teardown before/after fuzz tests Prevents bricking the device with garbage SSID/ntp_interval=0 etc. Safe values are restored after every fuzz suite run.	2026-05-18 20:44:07 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	5b8a58715e	feat: triple power-cycle factory reset (no FTDI needed) Power-cycle the device 3 times within 10 seconds to trigger factory reset: - Clears WiFi credentials (SSID + password) in EEPROM - Shows "FACTORY RESET / WiFi: TJ56654-Setup / Pass: 12345678" on display - Reboots into WiFiManager AP mode for reconfiguration Counter stored at EEPROM offset 480 (well past Config ~260 bytes). Clears automatically after 10s of stable operation. Prevents the need for FTDI/USB recovery when credentials are corrupted. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-18 20:25:32 +01:00
Alex Petrochenko	e9dc158a4e	chore: bump version to 1.9.6, update CHANGELOG	2026-05-18 16:02:53 +01:00
Alex Petrochenko	7ebe341c06	fix(web): clamp lastError before snprintf to prevent malformed JSON (Gemini review)	2026-05-18 15:57:41 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	78bbd96f45	fix: C1 C2 H1 H2 H3 — stability fixes for long-running operation C1 (critical): Add 15s watchdog for WEATHER_REQUESTING state — resets to IDLE if TCP connection hangs silently, preventing permanent weather death C2 (critical): Fix millis() rollover in all retry timers — replace unsafe `millis() >= nextRetryTime` with subtraction-safe `(millis() - nextRetryTime) < 0x80000000UL` in RetryConfig and WiFiRetryConfig; fix boot guard with static flag instead of raw millis() comparison H1 (high): Fix DST last-Sunday formula — was using incorrect year-only heuristic; now derives weekday of the 31st from current day's tm_wday: `weekdayOf31 = (tm_wday + (31 - day)) % 7`. Verified: March 2026 = 29th ✓ H2 (high): Replace String+= with snprintf+sendContent in handleAPITime, handleAPIStatus, handleAPIDebug, handleAPIWeather — eliminates permanent heap fragmentation from JS polling every second H3 (high): Add volatile to weatherState and ntpState — shared between ESPAsyncTCP callbacks and main loop; prevents stale register-cached reads RAM: 37,268 bytes (46%) — reduced from 37,560 due to String elimination Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-18 15:53:39 +01:00
Alex Petrochenko	eeec0155c3	chore: ignore internal BACKLOG files	2026-05-18 15:25:34 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	d5d2b23129	chore: bump version to 1.9.5, update CHANGELOG Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-18 14:53:15 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	2f3814c225	fix(weather): recover from permanent lockup after max retries (closes #9 ) After 3 consecutive API failures, weatherRetry.reset() was never called and weatherState stayed WEATHER_FAILED permanently. Both the retry path and periodic refresh path require WEATHER_IDLE, so no new requests were ever made — even after the API recovered. Fix: when maxRetriesReached(), reset weatherRetry and set weatherState back to WEATHER_IDLE so the next periodic refresh interval (default 30min) triggers a fresh attempt automatically. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-18 14:52:42 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	e4ef5c8e07	chore: bump version to 1.9.4, update docs - FIRMWARE_VERSION 1.9.3 → 1.9.4 - CHANGELOG: add v1.9.3 (modular refactor) and v1.9.4 (bug fixes) entries - README: add v1.9.3/v1.9.4 journey sections, fix project structure tree, update version references, correct SDK credentials description Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 18:52:26 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	3a34244ac8	refactor: rename firmware directory to weather_clock clock_ntp_ota_v1.9/ → weather_clock/ (version no longer baked into path) clock_ntp_ota_v1.9.ino → weather_clock.ino Version is tracked in config.h (FIRMWARE_VERSION), not in filenames. Updated references in README, CONTRIBUTING, and docs/INSTALLATION.md. Note: forks using the old path will need to sync this rename before submitting new PRs. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:52:34 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	55bec76d88	chore: remove internal version notes, clean up CHANGELOG links docs/v1.9_RELEASE_NOTES.md, v1.9.1_HYBRID_FIX.md, v1.9.2_WIFI_RESILIENCE.md were internal working documents (incomplete checklists, dev notes). CHANGELOG.md already covers all versions — links removed, status updated to v1.9.3. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:42:59 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	29d7c7f8ad	chore: remove monolithic src/ copy, firmware/ is now canonical src/clock_ntp_ota_v1.9.ino was a duplicate of firmware/clock_ntp_ota_v1.9/ that had already drifted out of sync. Removing it eliminates the need to patch both copies on every PR. Updated CONTRIBUTING.md build path to point to firmware/clock_ntp_ota_v1.9. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:40:36 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	98b40ff0cf	chore: remove internal dev documents from public repo PROJECT_CONTEXT.md, PROJECT_STRUCTURE.md, PUBLISH_TO_GITHUB.md were working notes not intended for contributors. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:40:04 +01:00
Alex Petrochenko waltje Claude Sonnet 4.6	8d404506c4	fix: resolve compiler warnings (from PR #8 by @waltje) - weather.cpp: StaticJsonDocument → JsonDocument (ArduinoJson v7 API) - display.cpp: daylightStr buffer 16 → 32 bytes (suppress GCC sprintf warning) - ntp_client.cpp: remove unused weekday variable Applied manually due to repo layout mismatch in original PR. Co-authored-by: waltje <waltje@users.noreply.github.com> Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:34:35 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	09b8680408	fix(wifi): skip SDK-cached credentials when SSID is already configured (closes #3 ) WiFi.begin() without params connects to any SDK-cached network, including open public hotspots, and then overwrites config.ssid with the wrong SSID. Now Try 1 (SDK credentials) is only attempted on first boot when no SSID is configured. Once the user has saved credentials, we go straight to Try 2 (EEPROM config), so the correct network is always used. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:29:47 +01:00
Alex PetrochenkoandClaude Sonnet 4.6	c606bcc589	docs: add ArduinoJson to required libraries list (closes #4 ) Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:24:17 +01:00
Alex Petrochenko Mysteoa Claude Sonnet 4.6	441c61676b	fix: date timezone + weather periodic refresh (closes #5 , #7 ) - Use localTime instead of epochTime when formatting date string, so date rolls over at local midnight, not UTC midnight (fixes #5) - Remove WEATHER_SUCCESS state assignment that blocked periodic refresh; state correctly stays WEATHER_IDLE after successful fetch (fixes #7) - Fix weather debug page "Last update" to show elapsed seconds (millis() - lastUpdate) instead of raw timestamp Applied from PR #6 by @Mysteoa with a compilation fix in web_server.cpp (missing closing parenthesis in snprintf_P call). Co-authored-by: Mysteoa <mysteoa@users.noreply.github.com> Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-14 17:20:08 +01:00