debug mode added for memory testing

platformio.ini

@@ -63,3 +63,11 @@ extends = base
 build_flags =
   ${base.build_flags}
   -DCROSSPOINT_VERSION=\"${crosspoint.version}\"
+
+[env:debug_memory]
+extends = base
+build_flags =
+  ${base.build_flags}
+  -DCROSSPOINT_VERSION=\"${crosspoint.version}-dev\"
+  -DDEBUG_MEMORY=1
+  -DCORE_DEBUG_LEVEL=4

src/activities/browser/OpdsBookBrowserActivity.cpp

@@ -60,6 +60,7 @@ void OpdsBookBrowserActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/dictionary/DictionaryMenuActivity.cpp

@@ -45,6 +45,7 @@ void DictionaryMenuActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/dictionary/DictionaryResultActivity.cpp

@@ -40,6 +40,7 @@ void DictionaryResultActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/dictionary/DictionarySearchActivity.cpp

@@ -88,6 +88,7 @@ void DictionarySearchActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/dictionary/EpubWordSelectionActivity.cpp

@@ -42,6 +42,7 @@ void EpubWordSelectionActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/home/HomeActivity.cpp

@@ -39,6 +39,10 @@ int HomeActivity::getMenuItemCount() const {
 void HomeActivity::onEnter() {
   Activity::onEnter();
 
+  Serial.printf("[%lu] [HOME] [MEM] onEnter - Free: %d, Largest: %d, CoverBuffer: %s (%d bytes)\n", millis(),
+                ESP.getFreeHeap(), ESP.getMaxAllocHeap(), coverBufferStored ? "allocated" : "null",
+                coverBufferStored ? static_cast<int>(GfxRenderer::getBufferSize()) : 0);
+
   renderingMutex = xSemaphoreCreateMutex();
 
   // Check if we have a book to continue reading
@@ -153,17 +157,24 @@ void HomeActivity::onEnter() {
 void HomeActivity::onExit() {
   Activity::onExit();
 
+  Serial.printf("[%lu] [HOME] [MEM] onExit start - Free: %d, Largest: %d, CoverBuffer: %s\n", millis(),
+                ESP.getFreeHeap(), ESP.getMaxAllocHeap(), coverBufferStored ? "allocated" : "null");
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;
 
   // NOTE: Do NOT free cover buffer here - keep it cached for fast re-entry
   // The buffer will be freed/replaced when the book changes
+
+  Serial.printf("[%lu] [HOME] [MEM] onExit end - Free: %d, Largest: %d\n", millis(), ESP.getFreeHeap(),
+                ESP.getMaxAllocHeap());
 }
 
 bool HomeActivity::storeCoverBuffer() {
@@ -202,8 +213,11 @@ bool HomeActivity::restoreCoverBuffer() {
 
 void HomeActivity::freeCoverBuffer() {
   if (coverBuffer) {
+    Serial.printf("[%lu] [HOME] [MEM] Freeing cover buffer (%d bytes), heap before: %d\n", millis(),
+                  static_cast<int>(GfxRenderer::getBufferSize()), ESP.getFreeHeap());
     free(coverBuffer);
     coverBuffer = nullptr;
+    Serial.printf("[%lu] [HOME] [MEM] Cover buffer freed, heap after: %d\n", millis(), ESP.getFreeHeap());
   }
   coverBufferStored = false;
 }

src/activities/home/ListViewActivity.cpp

@@ -96,6 +96,7 @@ void ListViewActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/home/MyLibraryActivity.cpp

@@ -188,6 +188,7 @@ void MyLibraryActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/network/CalibreWirelessActivity.cpp

@@ -82,6 +82,7 @@ void CalibreWirelessActivity::onExit() {
   if (networkTaskHandle) {
     vTaskDelete(networkTaskHandle);
     networkTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   xSemaphoreGive(stateMutex);
 
@@ -90,6 +91,7 @@ void CalibreWirelessActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/network/CrossPointWebServerActivity.cpp

@@ -5,6 +5,7 @@
 #include <GfxRenderer.h>
 #include <WiFi.h>
 #include <esp_task_wdt.h>
+#include <esp_wifi.h>
 #include <qrcode.h>
 
 #include <cstddef>
@@ -94,15 +95,18 @@ void CrossPointWebServerActivity::onEnter() {
 void CrossPointWebServerActivity::onExit() {
   ActivityWithSubactivity::onExit();
 
-  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit start: %d, Largest: %d\n", millis(), ESP.getFreeHeap(),
+                ESP.getMaxAllocHeap());
 
   state = WebServerActivityState::SHUTTING_DOWN;
 
   // Stop the web server first (before disconnecting WiFi)
   stopWebServer();
+  Serial.printf("[%lu] [WEBACT] [MEM] After stopWebServer: %d bytes\n", millis(), ESP.getFreeHeap());
 
   // Stop mDNS
   MDNS.end();
+  Serial.printf("[%lu] [WEBACT] [MEM] After MDNS.end: %d bytes\n", millis(), ESP.getFreeHeap());
 
   // Stop DNS server if running (AP mode)
   if (dnsServer) {
@@ -110,6 +114,7 @@ void CrossPointWebServerActivity::onExit() {
     dnsServer->stop();
     delete dnsServer;
     dnsServer = nullptr;
+    Serial.printf("[%lu] [WEBACT] [MEM] After DNS server cleanup: %d bytes\n", millis(), ESP.getFreeHeap());
   }
 
   // Brief wait for LWIP stack to flush pending packets
@@ -120,16 +125,24 @@ void CrossPointWebServerActivity::onExit() {
     Serial.printf("[%lu] [WEBACT] Stopping WiFi AP...\n", millis());
     WiFi.softAPdisconnect(true);
   } else {
-    Serial.printf("[%lu] [WEBACT] Disconnecting WiFi (graceful)...\n", millis());
-    WiFi.disconnect(false);  // false = don't erase credentials, send disconnect frame
+    Serial.printf("[%lu] [WEBACT] Disconnecting WiFi...\n", millis());
+    WiFi.disconnect(false);  // false = don't erase credentials, just send disconnect frame
   }
-  delay(30);  // Allow disconnect frame to be sent
+  delay(100);  // Allow disconnect frame to be sent and event callbacks to complete
+  Serial.printf("[%lu] [WEBACT] [MEM] After WiFi disconnect: %d bytes\n", millis(), ESP.getFreeHeap());
 
   Serial.printf("[%lu] [WEBACT] Setting WiFi mode OFF...\n", millis());
   WiFi.mode(WIFI_OFF);
-  delay(30);  // Allow WiFi hardware to power down
+  delay(50);
+  Serial.printf("[%lu] [WEBACT] [MEM] After WiFi.mode(OFF): %d bytes\n", millis(), ESP.getFreeHeap());
 
-  Serial.printf("[%lu] [WEBACT] [MEM] Free heap after WiFi disconnect: %d bytes\n", millis(), ESP.getFreeHeap());
+  // Aggressive WiFi cleanup: stop the WiFi driver to recover more memory
+  // WiFi is on-demand for File Transfer only, so full cleanup is safe
+  Serial.printf("[%lu] [WEBACT] Stopping WiFi driver (esp_wifi_stop)...\n", millis());
+  esp_wifi_stop();
+  delay(100);  // Allow LWIP stack to fully release
+  Serial.printf("[%lu] [WEBACT] [MEM] After esp_wifi_stop: %d, Largest: %d\n", millis(), ESP.getFreeHeap(),
+                ESP.getMaxAllocHeap());
 
   // Acquire mutex before deleting task
   Serial.printf("[%lu] [WEBACT] Acquiring rendering mutex before task deletion...\n", millis());
@@ -140,16 +153,18 @@ void CrossPointWebServerActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
-    Serial.printf("[%lu] [WEBACT] Display task deleted\n", millis());
+    // Allow idle task to free the task stack
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+    Serial.printf("[%lu] [WEBACT] [MEM] After task delete + yield: %d bytes\n", millis(), ESP.getFreeHeap());
   }
 
   // Delete the mutex
   Serial.printf("[%lu] [WEBACT] Deleting mutex...\n", millis());
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;
-  Serial.printf("[%lu] [WEBACT] Mutex deleted\n", millis());
 
-  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit end: %d, Largest: %d, MinFree: %d\n", millis(),
+                ESP.getFreeHeap(), ESP.getMaxAllocHeap(), ESP.getMinFreeHeap());
 }
 
 void CrossPointWebServerActivity::onNetworkModeSelected(const NetworkMode mode) {

src/activities/network/NetworkModeSelectionActivity.cpp

@@ -44,6 +44,7 @@ void NetworkModeSelectionActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/network/WifiSelectionActivity.cpp

@@ -82,6 +82,7 @@ void WifiSelectionActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
     Serial.printf("[%lu] [WIFI] Display task deleted\n", millis());
   }
 

src/activities/reader/EpubReaderActivity.cpp

@@ -192,6 +192,7 @@ void EpubReaderActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/reader/EpubReaderChapterSelectionActivity.cpp

@@ -88,6 +88,7 @@ void EpubReaderChapterSelectionActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/reader/TxtReaderActivity.cpp

@@ -131,6 +131,7 @@ void TxtReaderActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/reader/XtcReaderActivity.cpp

@@ -109,6 +109,7 @@ void XtcReaderActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/reader/XtcReaderChapterSelectionActivity.cpp

@@ -69,6 +69,7 @@ void XtcReaderChapterSelectionActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/settings/CalibreSettingsActivity.cpp

@@ -44,6 +44,7 @@ void CalibreSettingsActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/settings/CategorySettingsActivity.cpp

@@ -63,6 +63,7 @@ void CategorySettingsActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/settings/ClearCacheActivity.cpp

@@ -35,6 +35,7 @@ void ClearCacheActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/settings/OtaUpdateActivity.cpp

@@ -90,6 +90,7 @@ void OtaUpdateActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/settings/SettingsActivity.cpp

@@ -115,6 +115,7 @@ void SettingsActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/activities/util/KeyboardEntryActivity.cpp

@@ -55,6 +55,7 @@ void KeyboardEntryActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;

src/main.cpp

@@ -114,17 +114,38 @@ EpdFontFamily ui12FontFamily(&ui12RegularFont, &ui12BoldFont);
 unsigned long t1 = 0;
 unsigned long t2 = 0;
 
+// Memory debugging helper - logs heap state for tracking leaks
+#ifdef DEBUG_MEMORY
+void logMemoryState(const char* tag, const char* context) {
+  Serial.printf("[%lu] [%s] [MEM] %s - Free: %d, Largest: %d, MinFree: %d\n",
+    millis(), tag, context,
+    ESP.getFreeHeap(),
+    ESP.getMaxAllocHeap(),
+    ESP.getMinFreeHeap());
+}
+#else
+// No-op when not in debug mode
+#define logMemoryState(tag, context) ((void)0)
+#endif
+
 void exitActivity() {
   if (currentActivity) {
+    logMemoryState("MAIN", "Before onExit");
     currentActivity->onExit();
+    logMemoryState("MAIN", "After onExit, before delete");
     delete currentActivity;
     currentActivity = nullptr;
+    // Allow idle task to free FreeRTOS task stacks
+    delay(50);
+    logMemoryState("MAIN", "After delete + delay");
   }
 }
 
 void enterNewActivity(Activity* activity) {
+  logMemoryState("MAIN", "Before enterNewActivity");
   currentActivity = activity;
   currentActivity->onEnter();
+  logMemoryState("MAIN", "After onEnter");
 }
 
 // Verify long press on wake-up from deep sleep