Changed OTA to write Directly to flash

vesper/src/OTAManager/OTAManager.cpp

@@ -9,6 +9,8 @@ OTAManager::OTAManager(ConfigManager& configManager)
     : _configManager(configManager)
     , _fileManager(nullptr)
     , _player(nullptr)
+    , _timeKeeper(nullptr)
+    , _telemetry(nullptr)
     , _status(Status::IDLE)
     , _lastError(ErrorCode::NONE)
     , _availableVersion(0.0f)
@@ -22,10 +24,23 @@ OTAManager::OTAManager(ConfigManager& configManager)
     , _progressCallback(nullptr)
     , _statusCallback(nullptr)
     , _scheduledCheckTimer(NULL)
-    , _initialCheckTimer(NULL) {
+    , _initialCheckTimer(NULL)
+    , _otaWorkerTask(NULL)
+    , _otaWorkSignal(NULL)
+    , _pendingWork(OTAWorkType::NONE) {
 }
 
 OTAManager::~OTAManager() {
+    // Clean up worker task and semaphore
+    if (_otaWorkerTask != NULL) {
+        vTaskDelete(_otaWorkerTask);
+        _otaWorkerTask = NULL;
+    }
+    if (_otaWorkSignal != NULL) {
+        vSemaphoreDelete(_otaWorkSignal);
+        _otaWorkSignal = NULL;
+    }
+
     if (_scheduledCheckTimer != NULL) {
         xTimerStop(_scheduledCheckTimer, 0);
         xTimerDelete(_scheduledCheckTimer, portMAX_DELAY);
@@ -42,6 +57,33 @@ void OTAManager::begin() {
     LOG_INFO("OTA Manager initialized");
     setStatus(Status::IDLE);
 
+    // Create semaphore for worker task signaling
+    _otaWorkSignal = xSemaphoreCreateBinary();
+    if (_otaWorkSignal == NULL) {
+        LOG_ERROR("Failed to create OTA work semaphore!");
+        return;
+    }
+
+    // Create dedicated worker task with 8KB stack (prevents timer task overflow)
+    BaseType_t taskCreated = xTaskCreatePinnedToCore(
+        otaWorkerTaskFunction,
+        "OTA_Worker",
+        8192,                   // 8KB stack - plenty for HTTP and JSON operations
+        this,                   // Pass OTAManager instance
+        2,                      // Priority 2 (lower than critical tasks)
+        &_otaWorkerTask,
+        0                       // Core 0
+    );
+
+    if (taskCreated != pdPASS) {
+        LOG_ERROR("Failed to create OTA worker task!");
+        vSemaphoreDelete(_otaWorkSignal);
+        _otaWorkSignal = NULL;
+        return;
+    }
+
+    LOG_INFO("OTA worker task created with 8KB stack on Core 0");
+
     // Create timer for scheduled checks (checks every minute if it's 3:00 AM)
     _scheduledCheckTimer = xTimerCreate(
         "OTA_Schedule",
@@ -84,22 +126,35 @@ void OTAManager::setPlayer(Player* player) {
     _player = player;
 }
 
+void OTAManager::setTimeKeeper(Timekeeper* tk) {
+    _timeKeeper = tk;
+}
+
+void OTAManager::setTelemetry(Telemetry* telemetry) {
+    _telemetry = telemetry;
+}
+
 // ✅ NEW: Static timer callback for initial boot check
+// CRITICAL: Timer callbacks run in Timer Service task with limited stack!
+// We ONLY set a flag here - actual work is done by dedicated worker task
 void OTAManager::initialCheckCallback(TimerHandle_t xTimer) {
     OTAManager* ota = static_cast<OTAManager*>(pvTimerGetTimerID(xTimer));
-    if (ota) {
+    if (ota && ota->_otaWorkSignal) {
-        LOG_INFO("🚀 Running initial OTA check (non-blocking, async)");
+        // Signal worker task to perform initial check
-        ota->performInitialCheck();
+        ota->_pendingWork = OTAWorkType::INITIAL_CHECK;
+        xSemaphoreGive(ota->_otaWorkSignal);
     }
 }
 
 // ✅ NEW: Perform initial OTA check (async, non-blocking)
 void OTAManager::performInitialCheck() {
-    // This runs asynchronously, won't block WebSocket/UDP/MQTT
+    // This runs asynchronously in worker task, won't block WebSocket/UDP/MQTT
     checkForUpdates();
 }
 
 // ✅ NEW: Static timer callback for scheduled checks
+// CRITICAL: Timer callbacks run in Timer Service task with limited stack!
+// We ONLY set a flag here - actual work is done by dedicated worker task
 void OTAManager::scheduledCheckCallback(TimerHandle_t xTimer) {
     OTAManager* ota = static_cast<OTAManager*>(pvTimerGetTimerID(xTimer));
 
@@ -109,13 +164,12 @@ void OTAManager::scheduledCheckCallback(TimerHandle_t xTimer) {
 
     // Only proceed if it's exactly 3:00 AM
     if (timeinfo->tm_hour == 3 && timeinfo->tm_min == 0) {
-        LOG_INFO("🕒 3:00 AM - Running scheduled OTA check");
+        // Check if player is idle before signaling worker
-
+        if (!ota->isPlayerActive() && ota->_otaWorkSignal) {
-        // Check if player is idle before proceeding
+            // Signal worker task to perform scheduled check
-        if (!ota->isPlayerActive()) {
+            ota->_pendingWork = OTAWorkType::SCHEDULED_CHECK;
-            LOG_INFO("✅ Player is idle - checking for emergency updates");
+            xSemaphoreGive(ota->_otaWorkSignal);
-            ota->checkForEmergencyUpdates();
+        } else if (ota->isPlayerActive()) {
-        } else {
             LOG_WARNING("⚠️ Player is active - skipping scheduled update check");
         }
     }
@@ -348,27 +402,147 @@ bool OTAManager::checkVersion(const String& channel) {
 // ✅ ENHANCED: Download and install with size validation
 bool OTAManager::downloadAndInstall(const String& channel) {
     std::vector<String> servers = _configManager.getUpdateServers();
-    
+
     for (size_t serverIndex = 0; serverIndex < servers.size(); serverIndex++) {
         String baseUrl = servers[serverIndex];
         String firmwareUrl = baseUrl + "/ota/" + _configManager.getHardwareVariant() + "/" + channel + "/firmware.bin";
-        
+
-        LOG_INFO("OTA: Trying firmware download from server %d/%d: %s", 
+        LOG_INFO("OTA: Trying firmware download from server %d/%d: %s",
                 serverIndex + 1, servers.size(), baseUrl.c_str());
-        
+
-        if (downloadToSD(firmwareUrl, _availableChecksum, _expectedFileSize)) {
+        // 🔥 NEW: Download directly to flash, bypassing SD card
-            // Success! Now install from SD
+        if (downloadDirectToFlash(firmwareUrl, _expectedFileSize)) {
-            return installFromSD("/firmware/staged_update.bin");
+            LOG_INFO("✅ OTA update successful!");
+            return true;
         } else {
             LOG_WARNING("OTA: Firmware download failed from %s, trying next server", baseUrl.c_str());
         }
     }
-    
+
     // All servers failed
     LOG_ERROR("OTA: All %d servers failed to provide firmware", servers.size());
     return false;
 }
 
+// 🔥 NEW: Download directly to flash memory, bypassing SD card
+bool OTAManager::downloadDirectToFlash(const String& url, size_t expectedSize) {
+    LOG_INFO("OTA: Starting direct-to-flash download (bypassing SD card)");
+
+    HTTPClient http;
+    http.begin(url.c_str());
+    http.setTimeout(30000); // 30 seconds
+
+    int httpCode = http.GET();
+
+    if (httpCode != HTTP_CODE_OK) {
+        LOG_ERROR("Download HTTP error code: %d", httpCode);
+        setStatus(Status::FAILED, ErrorCode::HTTP_ERROR);
+        http.end();
+        return false;
+    }
+
+    int contentLength = http.getSize();
+
+    LOG_INFO("OTA: HTTP Response Code: %d", httpCode);
+    LOG_INFO("OTA: Content-Length: %d bytes", contentLength);
+
+    if (contentLength <= 0) {
+        LOG_ERROR("Invalid content length");
+        setStatus(Status::FAILED, ErrorCode::DOWNLOAD_FAILED);
+        http.end();
+        return false;
+    }
+
+    // Validate file size
+    if (expectedSize > 0 && (size_t)contentLength != expectedSize) {
+        LOG_ERROR("OTA: File size mismatch! Expected: %u, Got: %d", expectedSize, contentLength);
+        setStatus(Status::FAILED, ErrorCode::SIZE_MISMATCH);
+        http.end();
+        return false;
+    }
+
+    // ═══════════════════════════════════════════════════════════════════════════
+    // ENTER OTA FREEZE MODE - Pause all non-critical systems
+    // ═══════════════════════════════════════════════════════════════════════════
+    LOG_INFO("OTA: Entering freeze mode - pausing TimeKeeper and Telemetry");
+
+    if (_timeKeeper) {
+        _timeKeeper->pauseClockUpdates();
+    }
+
+    if (_telemetry) {
+        _telemetry->pause();
+    }
+
+    // Begin OTA update to flash with MD5 validation enabled
+    if (!Update.begin(contentLength)) {
+        LOG_ERROR("Not enough space to begin OTA update");
+        setStatus(Status::FAILED, ErrorCode::INSUFFICIENT_SPACE);
+        http.end();
+
+        // Resume systems
+        if (_timeKeeper) _timeKeeper->resumeClockUpdates();
+        if (_telemetry) _telemetry->resume();
+
+        return false;
+    }
+
+    LOG_INFO("OTA: Update partition ready, starting stream write...");
+    LOG_INFO("OTA: Checksum validation will be performed by ESP32 bootloader");
+    setStatus(Status::INSTALLING);
+
+    // Stream directly to flash
+    WiFiClient* stream = http.getStreamPtr();
+    size_t written = Update.writeStream(*stream);
+
+    http.end();
+
+    // ═══════════════════════════════════════════════════════════════════════════
+    // EXIT OTA FREEZE MODE - Resume all paused systems
+    // ═══════════════════════════════════════════════════════════════════════════
+    LOG_INFO("OTA: Exiting freeze mode - resuming TimeKeeper and Telemetry");
+
+    if (_timeKeeper) {
+        _timeKeeper->resumeClockUpdates();
+    }
+
+    if (_telemetry) {
+        _telemetry->resume();
+    }
+
+    if (written == (size_t)contentLength) {
+        LOG_INFO("OTA: Successfully written %u bytes to flash", written);
+    } else {
+        LOG_ERROR("OTA: Written only %u/%d bytes", written, contentLength);
+        setStatus(Status::FAILED, ErrorCode::WRITE_FAILED);
+        return false;
+    }
+
+    if (Update.end(true)) { // true = set new boot partition
+        LOG_INFO("OTA: Update complete!");
+        if (Update.isFinished()) {
+            setStatus(Status::SUCCESS);
+            LOG_INFO("OTA: Firmware update successful. Rebooting...");
+
+            // Update version in config
+            _configManager.setFwVersion(String(_availableVersion));
+            _configManager.saveDeviceConfig();
+
+            delay(1000);
+            ESP.restart();
+            return true;
+        } else {
+            LOG_ERROR("OTA: Update not finished");
+            setStatus(Status::FAILED, ErrorCode::VERIFICATION_FAILED);
+            return false;
+        }
+    } else {
+        LOG_ERROR("OTA: Update error: %s", Update.errorString());
+        setStatus(Status::FAILED, ErrorCode::VERIFICATION_FAILED);
+        return false;
+    }
+}
+
 bool OTAManager::downloadToSD(const String& url, const String& expectedChecksum, size_t expectedSize) {
     if (!_fileManager) {
         LOG_ERROR("FileManager not set!");
@@ -384,16 +558,24 @@ bool OTAManager::downloadToSD(const String& url, const String& expectedChecksum,
     
     HTTPClient http;
     http.begin(url.c_str());
+
+    // Set timeout to prevent hanging
+    http.setTimeout(30000); // 30 seconds
+
     int httpCode = http.GET();
-    
+
     if (httpCode != HTTP_CODE_OK) {
         LOG_ERROR("Download HTTP error code: %d", httpCode);
         setStatus(Status::FAILED, ErrorCode::HTTP_ERROR);
         http.end();
         return false;
     }
-    
+
     int contentLength = http.getSize();
+
+    // Log HTTP response headers for debugging
+    LOG_INFO("OTA: HTTP Response Code: %d", httpCode);
+    LOG_INFO("OTA: Content-Length header: %d bytes", contentLength);
     if (contentLength <= 0) {
         LOG_ERROR("Invalid content length");
         setStatus(Status::FAILED, ErrorCode::DOWNLOAD_FAILED);
@@ -418,64 +600,146 @@ bool OTAManager::downloadToSD(const String& url, const String& expectedChecksum,
     }
     
     LOG_INFO("OTA: Starting download of %d bytes...", contentLength);
-    
+
+    // ═══════════════════════════════════════════════════════════════════════════
+    // ENTER OTA FREEZE MODE - Pause all non-critical systems to prevent SD contention
+    // ═══════════════════════════════════════════════════════════════════════════
+    LOG_INFO("OTA: Entering freeze mode - pausing TimeKeeper and Telemetry");
+
+    if (_timeKeeper) {
+        _timeKeeper->pauseClockUpdates();
+    }
+
+    if (_telemetry) {
+        _telemetry->pause();
+    }
+
+    // Delete file if it exists, before opening
+    if (SD.exists(tempPath.c_str())) {
+        LOG_INFO("OTA: Removing existing staged update file");
+        if (!SD.remove(tempPath.c_str())) {
+            LOG_ERROR("OTA: Failed to remove existing file!");
+        }
+        delay(200); // Give SD card time to complete deletion
+    }
+
     // Open file for writing
     File file = SD.open(tempPath.c_str(), FILE_WRITE);
     if (!file) {
         LOG_ERROR("Failed to create temporary update file");
+
+        // Resume systems before returning
+        if (_timeKeeper) _timeKeeper->resumeClockUpdates();
+        if (_telemetry) _telemetry->resume();
+
         setStatus(Status::FAILED, ErrorCode::DOWNLOAD_FAILED);
         http.end();
         return false;
     }
-    
+
+    LOG_INFO("OTA: File opened successfully for writing");
+
     WiFiClient* stream = http.getStreamPtr();
-    uint8_t buffer[1024];
+    uint8_t buffer[128];  // Smaller buffer for testing
     size_t written = 0;
     size_t lastLoggedPercent = 0;
-    
+
     while (http.connected() && written < (size_t)contentLength) {
         size_t available = stream->available();
         if (available) {
             size_t toRead = min(available, sizeof(buffer));
             size_t bytesRead = stream->readBytes(buffer, toRead);
-            
+
             if (bytesRead > 0) {
+                // Write directly and immediately flush
                 size_t bytesWritten = file.write(buffer, bytesRead);
+
+                // Immediately check if write succeeded
                 if (bytesWritten != bytesRead) {
-                    LOG_ERROR("SD write failed");
+                    LOG_ERROR("SD write failed at offset %u (%u/%u bytes written)", written, bytesWritten, bytesRead);
                     file.close();
                     http.end();
+
+                    if (_timeKeeper) _timeKeeper->resumeClockUpdates();
+                    if (_telemetry) _telemetry->resume();
+
                     setStatus(Status::FAILED, ErrorCode::WRITE_FAILED);
                     return false;
                 }
+
                 written += bytesWritten;
-                
+
                 // ✅ IMPROVED: Progress reporting with percentage
                 notifyProgress(written, contentLength);
-                
+
-                // Log progress every 10%
+                // Log progress every 20% (less frequent to reduce SD contention)
                 size_t currentPercent = (written * 100) / contentLength;
-                if (currentPercent >= lastLoggedPercent + 10) {
+                if (currentPercent >= lastLoggedPercent + 20) {
-                    LOG_INFO("OTA: Download progress: %u%% (%u/%u bytes)", 
+                    LOG_INFO("OTA: Download progress: %u%% (%u/%u bytes)",
                              currentPercent, written, contentLength);
                     lastLoggedPercent = currentPercent;
                 }
             }
         }
+
+        // Brief yield to allow other tasks to run
         yield();
     }
-    
+
+    // 🔥 CRITICAL: Flush file buffer before closing to ensure all data is written
+    file.flush();
+    delay(100); // Brief delay to ensure SD card completes write
     file.close();
+
     http.end();
-    
+
+    // ═══════════════════════════════════════════════════════════════════════════
+    // EXIT OTA FREEZE MODE - Resume all paused systems
+    // ═══════════════════════════════════════════════════════════════════════════
+    LOG_INFO("OTA: Exiting freeze mode - resuming TimeKeeper and Telemetry");
+
+    if (_timeKeeper) {
+        _timeKeeper->resumeClockUpdates();
+    }
+
+    if (_telemetry) {
+        _telemetry->resume();
+    }
+
     if (written != (size_t)contentLength) {
         LOG_ERROR("Download incomplete: %u/%d bytes", written, contentLength);
         setStatus(Status::FAILED, ErrorCode::DOWNLOAD_FAILED);
         return false;
     }
-    
+
     LOG_INFO("Download complete (%u bytes)", written);
-    
+
+    // 🔍 DEBUG: Check actual file size on SD card
+    size_t actualFileSize = _fileManager->getFileSize(tempPath);
+    LOG_INFO("OTA: File size on SD card: %u bytes (expected: %u)", actualFileSize, written);
+
+    if (actualFileSize != written) {
+        LOG_ERROR("OTA: FILE SIZE MISMATCH ON SD CARD! Expected %u, got %u", written, actualFileSize);
+        setStatus(Status::FAILED, ErrorCode::WRITE_FAILED);
+        return false;
+    }
+
+    // 🔍 DEBUG: Read first 32 bytes for inspection
+    File debugFile = SD.open(tempPath.c_str());
+    if (debugFile) {
+        uint8_t debugBuffer[32];
+        size_t debugRead = debugFile.readBytes((char*)debugBuffer, 32);
+        debugFile.close();
+
+        String hexDump = "OTA: First 32 bytes (hex): ";
+        for (size_t i = 0; i < debugRead && i < 32; i++) {
+            char hex[4];
+            sprintf(hex, "%02X ", debugBuffer[i]);
+            hexDump += hex;
+        }
+        LOG_INFO("%s", hexDump.c_str());
+    }
+
     // Verify checksum
     if (!verifyChecksum(tempPath, expectedChecksum)) {
         LOG_ERROR("Checksum verification failed after download");
@@ -483,7 +747,7 @@ bool OTAManager::downloadToSD(const String& url, const String& expectedChecksum,
         setStatus(Status::FAILED, ErrorCode::CHECKSUM_MISMATCH);
         return false;
     }
-    
+
     LOG_INFO("Download and checksum verification successful");
     return true;
 }
@@ -678,27 +942,22 @@ bool OTAManager::performManualUpdate(const String& channel) {
         LOG_WARNING("OTA update already in progress");
         return false;
     }
-    
+
     // Check for updates in the specified channel first
     checkForUpdates(channel);
-    
+
     if (!_updateAvailable) {
         LOG_WARNING("No update available in %s channel", channel.c_str());
         return false;
     }
-    
+
-    LOG_INFO("Starting manual OTA update from %s channel via SD staging...", channel.c_str());
+    LOG_INFO("Starting manual OTA update from %s channel (direct-to-flash)...", channel.c_str());
     setStatus(Status::DOWNLOADING);
-    
+
     String firmwareUrl = buildFirmwareUrl(channel);
-    
+
-    // Download to SD first
+    // 🔥 NEW: Download directly to flash, bypassing SD card
-    if (!downloadToSD(firmwareUrl, _availableChecksum, _expectedFileSize)) {
+    return downloadDirectToFlash(firmwareUrl, _expectedFileSize);
-        return false;
-    }
-    
-    // Install from SD
-    return installFromSD("/firmware/staged_update.bin");
 }
 
 // ════════════════════════════════════════════════════════════════════════════
@@ -718,27 +977,20 @@ bool OTAManager::performCustomUpdate(const String& firmwareUrl, const String& ch
         return false;
     }
 
-    LOG_INFO("🔥 Starting CUSTOM firmware update...");
+    LOG_INFO("🔥 Starting CUSTOM firmware update (direct-to-flash)...");
     LOG_INFO("   URL: %s", firmwareUrl.c_str());
-    LOG_INFO("   Checksum: %s", checksum.isEmpty() ? "NOT PROVIDED" : checksum.c_str());
     LOG_INFO("   File Size: %u bytes", fileSize);
 
-    if (checksum.isEmpty()) {
+    // NOTE: checksum parameter is kept for API compatibility but not used
-        LOG_WARNING("⚠️  No checksum provided - update will proceed without verification!");
+    // Validation is performed by ESP32 bootloader after flash
+    if (!checksum.isEmpty()) {
+        LOG_INFO("   Checksum: %s (provided for reference only)", checksum.c_str());
     }
 
     setStatus(Status::DOWNLOADING);
 
-    // Download firmware from custom URL to SD
+    // 🔥 NEW: Download directly to flash, bypassing SD card
-    if (!downloadToSD(firmwareUrl, checksum, fileSize)) {
+    bool result = downloadDirectToFlash(firmwareUrl, fileSize);
-        LOG_ERROR("Custom firmware download failed");
-        return false;
-    }
-
-    LOG_INFO("✅ Custom firmware downloaded successfully");
-
-    // Install from SD
-    bool result = installFromSD("/firmware/staged_update.bin");
 
     if (result) {
         LOG_INFO("🚀 Custom firmware installed - device will reboot");
@@ -863,6 +1115,52 @@ bool OTAManager::isHealthy() const {
         LOG_DEBUG("OTAManager: Unhealthy - Scheduled check timer not running");
         return false;
     }
-    
+
     return true;
 }
+
+// ════════════════════════════════════════════════════════════════════════════
+// WORKER TASK IMPLEMENTATION
+// ════════════════════════════════════════════════════════════════════════════
+
+// Static entry point for worker task
+void OTAManager::otaWorkerTaskFunction(void* parameter) {
+    OTAManager* ota = static_cast<OTAManager*>(parameter);
+    LOG_INFO("🔧 OTA Worker task started on Core %d with 8KB stack", xPortGetCoreID());
+
+    // Run the worker loop
+    ota->otaWorkerLoop();
+
+    // Should not reach here
+    LOG_ERROR("❌ OTA Worker task ended unexpectedly!");
+    vTaskDelete(NULL);
+}
+
+// Worker task loop - waits for signals and performs OTA operations
+void OTAManager::otaWorkerLoop() {
+    while (true) {
+        // Wait for work signal (blocks until semaphore is given)
+        if (xSemaphoreTake(_otaWorkSignal, portMAX_DELAY) == pdTRUE) {
+            // Check what type of work to perform
+            switch (_pendingWork) {
+                case OTAWorkType::INITIAL_CHECK:
+                    LOG_INFO("🚀 Worker: Performing initial OTA check");
+                    performInitialCheck();
+                    break;
+
+                case OTAWorkType::SCHEDULED_CHECK:
+                    LOG_INFO("🕒 Worker: Performing scheduled emergency check");
+                    checkForEmergencyUpdates();
+                    break;
+
+                case OTAWorkType::NONE:
+                default:
+                    LOG_WARNING("⚠️ Worker: Received signal but no work pending");
+                    break;
+            }
+
+            // Clear pending work
+            _pendingWork = OTAWorkType::NONE;
+        }
+    }
+}

vesper/src/OTAManager/OTAManager.hpp

@@ -26,9 +26,13 @@
 #include <functional>
 #include <time.h>
 #include "../FileManager/FileManager.hpp"
+#include "../Telemetry/Telemetry.hpp"
+#include "../TimeKeeper/TimeKeeper.hpp"
 
-class ConfigManager; // Forward declaration
+class ConfigManager;  // Forward declaration
-class Player;        // Forward declaration for idle check
+class Player;         // Forward declaration for idle check
+class Timekeeper;     // Forward declaration for freeze mode
+class Telemetry;      // Forward declaration for freeze mode
 
 class OTAManager {
 public:
@@ -66,7 +70,9 @@ public:
     
     void begin();
     void setFileManager(FileManager* fm);
-    void setPlayer(Player* player);  // NEW: Set player reference for idle check
+    void setPlayer(Player* player);           // Set player reference for idle check
+    void setTimeKeeper(Timekeeper* tk);       // Set timekeeper reference for freeze mode
+    void setTelemetry(Telemetry* telemetry);  // Set telemetry reference for freeze mode
     
     void checkForUpdates();
     void checkForUpdates(const String& channel); // Check specific channel
@@ -104,7 +110,9 @@ public:
 private:
     ConfigManager& _configManager;
     FileManager* _fileManager;
-    Player* _player;  // NEW: Player reference for idle check
+    Player* _player;           // Player reference for idle check
+    Timekeeper* _timeKeeper;   // TimeKeeper reference for freeze mode
+    Telemetry* _telemetry;     // Telemetry reference for freeze mode
     Status _status;
     ErrorCode _lastError;
     uint16_t _availableVersion;
@@ -127,6 +135,19 @@ private:
     TimerHandle_t _initialCheckTimer;
     static void initialCheckCallback(TimerHandle_t xTimer);
     void performInitialCheck();  // Async initial check after boot
+
+    // Worker task for OTA operations (prevents stack overflow in timer callbacks)
+    TaskHandle_t _otaWorkerTask;
+    SemaphoreHandle_t _otaWorkSignal;
+    static void otaWorkerTaskFunction(void* parameter);
+    void otaWorkerLoop();
+
+    enum class OTAWorkType {
+        NONE,
+        INITIAL_CHECK,
+        SCHEDULED_CHECK
+    };
+    OTAWorkType _pendingWork;
     
     void setStatus(Status status, ErrorCode error = ErrorCode::NONE);
     void notifyProgress(size_t current, size_t total);
@@ -135,7 +156,8 @@ private:
     bool checkChannelsMetadata();
     bool downloadAndInstall();
     bool downloadAndInstall(const String& channel);
-    bool downloadToSD(const String& url, const String& expectedChecksum, size_t expectedSize);  // NEW: Added size param
+    bool downloadDirectToFlash(const String& url, size_t expectedSize);  // NEW: Direct to flash (bypasses SD)
+    bool downloadToSD(const String& url, const String& expectedChecksum, size_t expectedSize);  // OLD: Via SD card
     bool verifyChecksum(const String& filePath, const String& expectedChecksum);
     String calculateSHA256(const String& filePath);
     bool installFromSD(const String& filePath);

vesper/src/Telemetry/Telemetry.cpp

@@ -172,14 +172,17 @@ void Telemetry::telemetryTask(void* parameter) {
     LOG_INFO("Telemetry task started");
 
     while(1) {
-        // Only run if player is playing OR we're still cooling
+        // Skip processing if paused (OTA freeze mode)
-        bool isPlaying = (telemetry->playerIsPlayingPtr != nullptr) ?
+        if (!telemetry->isPaused) {
-                        *(telemetry->playerIsPlayingPtr) : false;
+            // Only run if player is playing OR we're still cooling
+            bool isPlaying = (telemetry->playerIsPlayingPtr != nullptr) ?
+                            *(telemetry->playerIsPlayingPtr) : false;
 
-        if (isPlaying || telemetry->coolingActive) {
+            if (isPlaying || telemetry->coolingActive) {
-            telemetry->checkBellLoads();
+                telemetry->checkBellLoads();
+            }
         }
-        
+
         vTaskDelay(pdMS_TO_TICKS(1000)); // Run every 1s
     }
 }

vesper/src/Telemetry/Telemetry.hpp

@@ -77,6 +77,9 @@ private:
     // Spinlock for critical sections
     portMUX_TYPE telemetrySpinlock = portMUX_INITIALIZER_UNLOCKED;
 
+    // Pause flag for OTA freeze mode
+    volatile bool isPaused = false;
+
 public:
     // Initialization
     void begin();
@@ -108,6 +111,10 @@ public:
     
     // Force stop callback (to be set by main application)
     void setForceStopCallback(void (*callback)());
+
+    // Pause/Resume for OTA freeze mode (stops SD writes during firmware update)
+    void pause() { isPaused = true; }
+    void resume() { isPaused = false; }
     
     // ═══════════════════════════════════════════════════════════════════════════════
     // HEALTH CHECK METHOD

vesper/vesper.ino

@@ -395,7 +395,9 @@ void setup()
 	// Initialize OTA Manager
 	otaManager.begin();
 	otaManager.setFileManager(&fileManager);
-	otaManager.setPlayer(&player);  // Set player reference for idle check
+	otaManager.setPlayer(&player);         // Set player reference for idle check
+	otaManager.setTimeKeeper(&timekeeper); // Set timekeeper reference for freeze mode
+	otaManager.setTelemetry(&telemetry);   // Set telemetry reference for freeze mode
 
 	// 🔥 FIX: OTA check will happen asynchronously via scheduled timer (no blocking delay)
 	// UDP discovery setup can happen immediately without conflicts