Adds KOReader Sync support (#232)

## Summary - Adds KOReader progress sync integration, allowing CrossPoint to sync reading positions with other KOReader-compatible devices - Stores credentials securely with XOR obfuscation - Uses KOReader's partial MD5 document hashing for cross-device book matching - Syncs position via percentage with estimated XPath for compatibility # Features - Settings: KOReader Username, Password, and Authenticate options - Sync from chapters menu: "Sync Progress" option appears when credentials are configured - Bidirectional sync: Can apply remote progress or upload local progress --------- Co-authored-by: Dave Allie <dave@daveallie.com>
2026-01-19 06:55:35 -05:00
parent 7185e5d287
commit f69cddf2cc
21 changed files with 1974 additions and 39 deletions
--- a/src/activities/reader/EpubReaderActivity.cpp
+++ b/src/activities/reader/EpubReaderActivity.cpp
@@ -118,9 +118,11 @@ void EpubReaderActivity::loop() {
  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
    // Don't start activity transition while rendering
    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    const int currentPage = section ? section->currentPage : 0;
+    const int totalPages = section ? section->pageCount : 0;
    exitActivity();
    enterNewActivity(new EpubReaderChapterSelectionActivity(
-        this->renderer, this->mappedInput, epub, currentSpineIndex,
+        this->renderer, this->mappedInput, epub, epub->getPath(), currentSpineIndex, currentPage, totalPages,
        [this] {
          exitActivity();
          updateRequired = true;
@@ -133,6 +135,16 @@ void EpubReaderActivity::loop() {
          }
          exitActivity();
          updateRequired = true;
+        },
+        [this](const int newSpineIndex, const int newPage) {
+          // Handle sync position
+          if (currentSpineIndex != newSpineIndex || (section && section->currentPage != newPage)) {
+            currentSpineIndex = newSpineIndex;
+            nextPageNumber = newPage;
+            section.reset();
+          }
+          exitActivity();
+          updateRequired = true;
        }));
    xSemaphoreGive(renderingMutex);
  }
@@ -430,11 +442,13 @@ void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const in
  if (showProgress) {
    // Calculate progress in book
    const float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
-    const uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
+    const float bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg) * 100;

    // Right aligned text for progress counter
-    const std::string progress = std::to_string(section->currentPage + 1) + "/" + std::to_string(section->pageCount) +
-                                 "  " + std::to_string(bookProgress) + "%";
+    char progressStr[32];
+    snprintf(progressStr, sizeof(progressStr), "%d/%d  %.1f%%", section->currentPage + 1, section->pageCount,
+             bookProgress);
+    const std::string progress = progressStr;
    progressTextWidth = renderer.getTextWidth(SMALL_FONT_ID, progress.c_str());
    renderer.drawText(SMALL_FONT_ID, renderer.getScreenWidth() - orientedMarginRight - progressTextWidth, textY,
                      progress.c_str());
--- a/src/activities/reader/EpubReaderChapterSelectionActivity.cpp
+++ b/src/activities/reader/EpubReaderChapterSelectionActivity.cpp
@@ -2,6 +2,8 @@

 #include <GfxRenderer.h>

+#include "KOReaderCredentialStore.h"
+#include "KOReaderSyncActivity.h"
 #include "MappedInputManager.h"
 #include "fontIds.h"

@@ -10,6 +12,26 @@ namespace {
 constexpr int SKIP_PAGE_MS = 700;
 }  // namespace

+bool EpubReaderChapterSelectionActivity::hasSyncOption() const { return KOREADER_STORE.hasCredentials(); }
+
+int EpubReaderChapterSelectionActivity::getTotalItems() const {
+  // Add 2 for sync options (top and bottom) if credentials are configured
+  const int syncCount = hasSyncOption() ? 2 : 0;
+  return epub->getTocItemsCount() + syncCount;
+}
+
+bool EpubReaderChapterSelectionActivity::isSyncItem(int index) const {
+  if (!hasSyncOption()) return false;
+  // First item and last item are sync options
+  return index == 0 || index == getTotalItems() - 1;
+}
+
+int EpubReaderChapterSelectionActivity::tocIndexFromItemIndex(int itemIndex) const {
+  // Account for the sync option at the top
+  const int offset = hasSyncOption() ? 1 : 0;
+  return itemIndex - offset;
+}
+
 int EpubReaderChapterSelectionActivity::getPageItems() const {
  // Layout constants used in renderScreen
  constexpr int startY = 60;
@@ -34,17 +56,21 @@ void EpubReaderChapterSelectionActivity::taskTrampoline(void* param) {
 }

 void EpubReaderChapterSelectionActivity::onEnter() {
-  Activity::onEnter();
+  ActivityWithSubactivity::onEnter();

  if (!epub) {
    return;
  }

  renderingMutex = xSemaphoreCreateMutex();
+
+  // Account for sync option offset when finding current TOC index
+  const int syncOffset = hasSyncOption() ? 1 : 0;
  selectorIndex = epub->getTocIndexForSpineIndex(currentSpineIndex);
  if (selectorIndex == -1) {
    selectorIndex = 0;
  }
+  selectorIndex += syncOffset;  // Offset for top sync option

  // Trigger first update
  updateRequired = true;
@@ -57,7 +83,7 @@ void EpubReaderChapterSelectionActivity::onEnter() {
 }

 void EpubReaderChapterSelectionActivity::onExit() {
-  Activity::onExit();
+  ActivityWithSubactivity::onExit();

  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
  xSemaphoreTake(renderingMutex, portMAX_DELAY);
@@ -69,7 +95,30 @@ void EpubReaderChapterSelectionActivity::onExit() {
  renderingMutex = nullptr;
 }

+void EpubReaderChapterSelectionActivity::launchSyncActivity() {
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  exitActivity();
+  enterNewActivity(new KOReaderSyncActivity(
+      renderer, mappedInput, epub, epubPath, currentSpineIndex, currentPage, totalPagesInSpine,
+      [this]() {
+        // On cancel
+        exitActivity();
+        updateRequired = true;
+      },
+      [this](int newSpineIndex, int newPage) {
+        // On sync complete
+        exitActivity();
+        onSyncPosition(newSpineIndex, newPage);
+      }));
+  xSemaphoreGive(renderingMutex);
+}
+
 void EpubReaderChapterSelectionActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
  const bool prevReleased = mappedInput.wasReleased(MappedInputManager::Button::Up) ||
                            mappedInput.wasReleased(MappedInputManager::Button::Left);
  const bool nextReleased = mappedInput.wasReleased(MappedInputManager::Button::Down) ||
@@ -77,9 +126,18 @@ void EpubReaderChapterSelectionActivity::loop() {

  const bool skipPage = mappedInput.getHeldTime() > SKIP_PAGE_MS;
  const int pageItems = getPageItems();
+  const int totalItems = getTotalItems();

  if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
-    const auto newSpineIndex = epub->getSpineIndexForTocIndex(selectorIndex);
+    // Check if sync option is selected (first or last item)
+    if (isSyncItem(selectorIndex)) {
+      launchSyncActivity();
+      return;
+    }
+
+    // Get TOC index (account for top sync offset)
+    const int tocIndex = tocIndexFromItemIndex(selectorIndex);
+    const auto newSpineIndex = epub->getSpineIndexForTocIndex(tocIndex);
    if (newSpineIndex == -1) {
      onGoBack();
    } else {
@@ -89,17 +147,16 @@ void EpubReaderChapterSelectionActivity::loop() {
    onGoBack();
  } else if (prevReleased) {
    if (skipPage) {
-      selectorIndex =
-          ((selectorIndex / pageItems - 1) * pageItems + epub->getTocItemsCount()) % epub->getTocItemsCount();
+      selectorIndex = ((selectorIndex / pageItems - 1) * pageItems + totalItems) % totalItems;
    } else {
-      selectorIndex = (selectorIndex + epub->getTocItemsCount() - 1) % epub->getTocItemsCount();
+      selectorIndex = (selectorIndex + totalItems - 1) % totalItems;
    }
    updateRequired = true;
  } else if (nextReleased) {
    if (skipPage) {
-      selectorIndex = ((selectorIndex / pageItems + 1) * pageItems) % epub->getTocItemsCount();
+      selectorIndex = ((selectorIndex / pageItems + 1) * pageItems) % totalItems;
    } else {
-      selectorIndex = (selectorIndex + 1) % epub->getTocItemsCount();
+      selectorIndex = (selectorIndex + 1) % totalItems;
    }
    updateRequired = true;
  }
@@ -107,7 +164,7 @@ void EpubReaderChapterSelectionActivity::loop() {

 void EpubReaderChapterSelectionActivity::displayTaskLoop() {
  while (true) {
-    if (updateRequired) {
+    if (updateRequired && !subActivity) {
      updateRequired = false;
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      renderScreen();
@@ -122,6 +179,7 @@ void EpubReaderChapterSelectionActivity::renderScreen() {

  const auto pageWidth = renderer.getScreenWidth();
  const int pageItems = getPageItems();
+  const int totalItems = getTotalItems();

  const std::string title =
      renderer.truncatedText(UI_12_FONT_ID, epub->getTitle().c_str(), pageWidth - 40, EpdFontFamily::BOLD);
@@ -129,11 +187,20 @@ void EpubReaderChapterSelectionActivity::renderScreen() {

  const auto pageStartIndex = selectorIndex / pageItems * pageItems;
  renderer.fillRect(0, 60 + (selectorIndex % pageItems) * 30 - 2, pageWidth - 1, 30);
-  for (int tocIndex = pageStartIndex; tocIndex < epub->getTocItemsCount() && tocIndex < pageStartIndex + pageItems;
-       tocIndex++) {
-    auto item = epub->getTocItem(tocIndex);
-    renderer.drawText(UI_10_FONT_ID, 20 + (item.level - 1) * 15, 60 + (tocIndex % pageItems) * 30, item.title.c_str(),
-                      tocIndex != selectorIndex);
+
+  for (int itemIndex = pageStartIndex; itemIndex < totalItems && itemIndex < pageStartIndex + pageItems; itemIndex++) {
+    const int displayY = 60 + (itemIndex % pageItems) * 30;
+    const bool isSelected = (itemIndex == selectorIndex);
+
+    if (isSyncItem(itemIndex)) {
+      // Draw sync option (at top or bottom)
+      renderer.drawText(UI_10_FONT_ID, 20, displayY, ">> Sync Progress", !isSelected);
+    } else {
+      // Draw TOC item (account for top sync offset)
+      const int tocIndex = tocIndexFromItemIndex(itemIndex);
+      auto item = epub->getTocItem(tocIndex);
+      renderer.drawText(UI_10_FONT_ID, 20 + (item.level - 1) * 15, displayY, item.title.c_str(), !isSelected);
+    }
  }

  const auto labels = mappedInput.mapLabels("« Back", "Select", "Up", "Down");
--- a/src/activities/reader/EpubReaderChapterSelectionActivity.h
+++ b/src/activities/reader/EpubReaderChapterSelectionActivity.h
@@ -6,36 +6,59 @@

 #include <memory>

-#include "../Activity.h"
+#include "../ActivityWithSubactivity.h"

-class EpubReaderChapterSelectionActivity final : public Activity {
+class EpubReaderChapterSelectionActivity final : public ActivityWithSubactivity {
  std::shared_ptr<Epub> epub;
+  std::string epubPath;
  TaskHandle_t displayTaskHandle = nullptr;
  SemaphoreHandle_t renderingMutex = nullptr;
  int currentSpineIndex = 0;
+  int currentPage = 0;
+  int totalPagesInSpine = 0;
  int selectorIndex = 0;
  bool updateRequired = false;
  const std::function<void()> onGoBack;
  const std::function<void(int newSpineIndex)> onSelectSpineIndex;
+  const std::function<void(int newSpineIndex, int newPage)> onSyncPosition;

  // Number of items that fit on a page, derived from logical screen height.
  // This adapts automatically when switching between portrait and landscape.
  int getPageItems() const;

+  // Total items including sync options (top and bottom)
+  int getTotalItems() const;
+
+  // Check if sync option is available (credentials configured)
+  bool hasSyncOption() const;
+
+  // Check if given item index is a sync option (first or last)
+  bool isSyncItem(int index) const;
+
+  // Convert item index to TOC index (accounting for top sync option offset)
+  int tocIndexFromItemIndex(int itemIndex) const;
+
  static void taskTrampoline(void* param);
  [[noreturn]] void displayTaskLoop();
  void renderScreen();
+  void launchSyncActivity();

 public:
  explicit EpubReaderChapterSelectionActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
-                                              const std::shared_ptr<Epub>& epub, const int currentSpineIndex,
-                                              const std::function<void()>& onGoBack,
-                                              const std::function<void(int newSpineIndex)>& onSelectSpineIndex)
-      : Activity("EpubReaderChapterSelection", renderer, mappedInput),
+                                              const std::shared_ptr<Epub>& epub, const std::string& epubPath,
+                                              const int currentSpineIndex, const int currentPage,
+                                              const int totalPagesInSpine, const std::function<void()>& onGoBack,
+                                              const std::function<void(int newSpineIndex)>& onSelectSpineIndex,
+                                              const std::function<void(int newSpineIndex, int newPage)>& onSyncPosition)
+      : ActivityWithSubactivity("EpubReaderChapterSelection", renderer, mappedInput),
        epub(epub),
+        epubPath(epubPath),
        currentSpineIndex(currentSpineIndex),
+        currentPage(currentPage),
+        totalPagesInSpine(totalPagesInSpine),
        onGoBack(onGoBack),
-        onSelectSpineIndex(onSelectSpineIndex) {}
+        onSelectSpineIndex(onSelectSpineIndex),
+        onSyncPosition(onSyncPosition) {}
  void onEnter() override;
  void onExit() override;
  void loop() override;
--- a/src/activities/reader/KOReaderSyncActivity.cpp
+++ b/src/activities/reader/KOReaderSyncActivity.cpp
@@ -0,0 +1,439 @@
+#include "KOReaderSyncActivity.h"
+
+#include <GfxRenderer.h>
+#include <WiFi.h>
+#include <esp_sntp.h>
+
+#include "KOReaderCredentialStore.h"
+#include "KOReaderDocumentId.h"
+#include "MappedInputManager.h"
+#include "activities/network/WifiSelectionActivity.h"
+#include "fontIds.h"
+
+namespace {
+void syncTimeWithNTP() {
+  // Stop SNTP if already running (can't reconfigure while running)
+  if (esp_sntp_enabled()) {
+    esp_sntp_stop();
+  }
+
+  // Configure SNTP
+  esp_sntp_setoperatingmode(ESP_SNTP_OPMODE_POLL);
+  esp_sntp_setservername(0, "pool.ntp.org");
+  esp_sntp_init();
+
+  // Wait for time to sync (with timeout)
+  int retry = 0;
+  const int maxRetries = 50;  // 5 seconds max
+  while (sntp_get_sync_status() != SNTP_SYNC_STATUS_COMPLETED && retry < maxRetries) {
+    vTaskDelay(100 / portTICK_PERIOD_MS);
+    retry++;
+  }
+
+  if (retry < maxRetries) {
+    Serial.printf("[%lu] [KOSync] NTP time synced\n", millis());
+  } else {
+    Serial.printf("[%lu] [KOSync] NTP sync timeout, using fallback\n", millis());
+  }
+}
+}  // namespace
+
+void KOReaderSyncActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<KOReaderSyncActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void KOReaderSyncActivity::onWifiSelectionComplete(const bool success) {
+  exitActivity();
+
+  if (!success) {
+    Serial.printf("[%lu] [KOSync] WiFi connection failed, exiting\n", millis());
+    onCancel();
+    return;
+  }
+
+  Serial.printf("[%lu] [KOSync] WiFi connected, starting sync\n", millis());
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = SYNCING;
+  statusMessage = "Syncing time...";
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+
+  // Sync time with NTP before making API requests
+  syncTimeWithNTP();
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  statusMessage = "Calculating document hash...";
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+
+  performSync();
+}
+
+void KOReaderSyncActivity::performSync() {
+  // Calculate document hash based on user's preferred method
+  if (KOREADER_STORE.getMatchMethod() == DocumentMatchMethod::FILENAME) {
+    documentHash = KOReaderDocumentId::calculateFromFilename(epubPath);
+  } else {
+    documentHash = KOReaderDocumentId::calculate(epubPath);
+  }
+  if (documentHash.empty()) {
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = SYNC_FAILED;
+    statusMessage = "Failed to calculate document hash";
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  Serial.printf("[%lu] [KOSync] Document hash: %s\n", millis(), documentHash.c_str());
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  statusMessage = "Fetching remote progress...";
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+  vTaskDelay(10 / portTICK_PERIOD_MS);
+
+  // Fetch remote progress
+  const auto result = KOReaderSyncClient::getProgress(documentHash, remoteProgress);
+
+  if (result == KOReaderSyncClient::NOT_FOUND) {
+    // No remote progress - offer to upload
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = NO_REMOTE_PROGRESS;
+    hasRemoteProgress = false;
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  if (result != KOReaderSyncClient::OK) {
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = SYNC_FAILED;
+    statusMessage = KOReaderSyncClient::errorString(result);
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  // Convert remote progress to CrossPoint position
+  hasRemoteProgress = true;
+  KOReaderPosition koPos = {remoteProgress.progress, remoteProgress.percentage};
+  remotePosition = ProgressMapper::toCrossPoint(epub, koPos, totalPagesInSpine);
+
+  // Calculate local progress in KOReader format (for display)
+  CrossPointPosition localPos = {currentSpineIndex, currentPage, totalPagesInSpine};
+  localProgress = ProgressMapper::toKOReader(epub, localPos);
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = SHOWING_RESULT;
+  selectedOption = 0;  // Default to "Apply"
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+}
+
+void KOReaderSyncActivity::performUpload() {
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = UPLOADING;
+  statusMessage = "Uploading progress...";
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+  vTaskDelay(10 / portTICK_PERIOD_MS);
+
+  // Convert current position to KOReader format
+  CrossPointPosition localPos = {currentSpineIndex, currentPage, totalPagesInSpine};
+  KOReaderPosition koPos = ProgressMapper::toKOReader(epub, localPos);
+
+  KOReaderProgress progress;
+  progress.document = documentHash;
+  progress.progress = koPos.xpath;
+  progress.percentage = koPos.percentage;
+
+  const auto result = KOReaderSyncClient::updateProgress(progress);
+
+  if (result != KOReaderSyncClient::OK) {
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = SYNC_FAILED;
+    statusMessage = KOReaderSyncClient::errorString(result);
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = UPLOAD_COMPLETE;
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+}
+
+void KOReaderSyncActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
+  renderingMutex = xSemaphoreCreateMutex();
+
+  xTaskCreate(&KOReaderSyncActivity::taskTrampoline, "KOSyncTask",
+              4096,               // Stack size (larger for network operations)
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+
+  // Check for credentials first
+  if (!KOREADER_STORE.hasCredentials()) {
+    state = NO_CREDENTIALS;
+    updateRequired = true;
+    return;
+  }
+
+  // Turn on WiFi
+  Serial.printf("[%lu] [KOSync] Turning on WiFi...\n", millis());
+  WiFi.mode(WIFI_STA);
+
+  // Check if already connected
+  if (WiFi.status() == WL_CONNECTED) {
+    Serial.printf("[%lu] [KOSync] Already connected to WiFi\n", millis());
+    state = SYNCING;
+    statusMessage = "Syncing time...";
+    updateRequired = true;
+
+    // Perform sync directly (will be handled in loop)
+    xTaskCreate(
+        [](void* param) {
+          auto* self = static_cast<KOReaderSyncActivity*>(param);
+          // Sync time first
+          syncTimeWithNTP();
+          xSemaphoreTake(self->renderingMutex, portMAX_DELAY);
+          self->statusMessage = "Calculating document hash...";
+          xSemaphoreGive(self->renderingMutex);
+          self->updateRequired = true;
+          self->performSync();
+          vTaskDelete(nullptr);
+        },
+        "SyncTask", 4096, this, 1, nullptr);
+    return;
+  }
+
+  // Launch WiFi selection subactivity
+  Serial.printf("[%lu] [KOSync] Launching WifiSelectionActivity...\n", millis());
+  enterNewActivity(new WifiSelectionActivity(renderer, mappedInput,
+                                             [this](const bool connected) { onWifiSelectionComplete(connected); }));
+}
+
+void KOReaderSyncActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
+  // Turn off wifi
+  WiFi.disconnect(false);
+  delay(100);
+  WiFi.mode(WIFI_OFF);
+  delay(100);
+
+  // Wait until not rendering to delete task
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+}
+
+void KOReaderSyncActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void KOReaderSyncActivity::render() {
+  if (subActivity) {
+    return;
+  }
+
+  const auto pageWidth = renderer.getScreenWidth();
+
+  renderer.clearScreen();
+  renderer.drawCenteredText(UI_12_FONT_ID, 15, "KOReader Sync", true, EpdFontFamily::BOLD);
+
+  if (state == NO_CREDENTIALS) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 280, "No credentials configured", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_10_FONT_ID, 320, "Set up KOReader account in Settings");
+
+    const auto labels = mappedInput.mapLabels("Back", "", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == SYNCING || state == UPLOADING) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 300, statusMessage.c_str(), true, EpdFontFamily::BOLD);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == SHOWING_RESULT) {
+    // Show comparison
+    renderer.drawCenteredText(UI_10_FONT_ID, 120, "Progress found!", true, EpdFontFamily::BOLD);
+
+    // Get chapter names from TOC
+    const int remoteTocIndex = epub->getTocIndexForSpineIndex(remotePosition.spineIndex);
+    const int localTocIndex = epub->getTocIndexForSpineIndex(currentSpineIndex);
+    const std::string remoteChapter = (remoteTocIndex >= 0)
+                                          ? epub->getTocItem(remoteTocIndex).title
+                                          : ("Section " + std::to_string(remotePosition.spineIndex + 1));
+    const std::string localChapter = (localTocIndex >= 0) ? epub->getTocItem(localTocIndex).title
+                                                          : ("Section " + std::to_string(currentSpineIndex + 1));
+
+    // Remote progress - chapter and page
+    renderer.drawText(UI_10_FONT_ID, 20, 160, "Remote:", true);
+    char remoteChapterStr[128];
+    snprintf(remoteChapterStr, sizeof(remoteChapterStr), "  %s", remoteChapter.c_str());
+    renderer.drawText(UI_10_FONT_ID, 20, 185, remoteChapterStr);
+    char remotePageStr[64];
+    snprintf(remotePageStr, sizeof(remotePageStr), "  Page %d, %.2f%% overall", remotePosition.pageNumber + 1,
+             remoteProgress.percentage * 100);
+    renderer.drawText(UI_10_FONT_ID, 20, 210, remotePageStr);
+
+    if (!remoteProgress.device.empty()) {
+      char deviceStr[64];
+      snprintf(deviceStr, sizeof(deviceStr), "  From: %s", remoteProgress.device.c_str());
+      renderer.drawText(UI_10_FONT_ID, 20, 235, deviceStr);
+    }
+
+    // Local progress - chapter and page
+    renderer.drawText(UI_10_FONT_ID, 20, 270, "Local:", true);
+    char localChapterStr[128];
+    snprintf(localChapterStr, sizeof(localChapterStr), "  %s", localChapter.c_str());
+    renderer.drawText(UI_10_FONT_ID, 20, 295, localChapterStr);
+    char localPageStr[64];
+    snprintf(localPageStr, sizeof(localPageStr), "  Page %d/%d, %.2f%% overall", currentPage + 1, totalPagesInSpine,
+             localProgress.percentage * 100);
+    renderer.drawText(UI_10_FONT_ID, 20, 320, localPageStr);
+
+    // Options
+    const int optionY = 350;
+    const int optionHeight = 30;
+
+    // Apply option
+    if (selectedOption == 0) {
+      renderer.fillRect(0, optionY - 2, pageWidth - 1, optionHeight);
+    }
+    renderer.drawText(UI_10_FONT_ID, 20, optionY, "Apply remote progress", selectedOption != 0);
+
+    // Upload option
+    if (selectedOption == 1) {
+      renderer.fillRect(0, optionY + optionHeight - 2, pageWidth - 1, optionHeight);
+    }
+    renderer.drawText(UI_10_FONT_ID, 20, optionY + optionHeight, "Upload local progress", selectedOption != 1);
+
+    // Cancel option
+    if (selectedOption == 2) {
+      renderer.fillRect(0, optionY + optionHeight * 2 - 2, pageWidth - 1, optionHeight);
+    }
+    renderer.drawText(UI_10_FONT_ID, 20, optionY + optionHeight * 2, "Cancel", selectedOption != 2);
+
+    const auto labels = mappedInput.mapLabels("", "Select", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == NO_REMOTE_PROGRESS) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 280, "No remote progress found", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_10_FONT_ID, 320, "Upload current position?");
+
+    const auto labels = mappedInput.mapLabels("Cancel", "Upload", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == UPLOAD_COMPLETE) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 300, "Progress uploaded!", true, EpdFontFamily::BOLD);
+
+    const auto labels = mappedInput.mapLabels("Back", "", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == SYNC_FAILED) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 280, "Sync failed", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_10_FONT_ID, 320, statusMessage.c_str());
+
+    const auto labels = mappedInput.mapLabels("Back", "", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+}
+
+void KOReaderSyncActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
+  if (state == NO_CREDENTIALS || state == SYNC_FAILED || state == UPLOAD_COMPLETE) {
+    if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
+      onCancel();
+    }
+    return;
+  }
+
+  if (state == SHOWING_RESULT) {
+    // Navigate options
+    if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
+        mappedInput.wasPressed(MappedInputManager::Button::Left)) {
+      selectedOption = (selectedOption + 2) % 3;  // Wrap around
+      updateRequired = true;
+    } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
+               mappedInput.wasPressed(MappedInputManager::Button::Right)) {
+      selectedOption = (selectedOption + 1) % 3;
+      updateRequired = true;
+    }
+
+    if (mappedInput.wasPressed(MappedInputManager::Button::Confirm)) {
+      if (selectedOption == 0) {
+        // Apply remote progress
+        onSyncComplete(remotePosition.spineIndex, remotePosition.pageNumber);
+      } else if (selectedOption == 1) {
+        // Upload local progress
+        performUpload();
+      } else {
+        // Cancel
+        onCancel();
+      }
+    }
+
+    if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
+      onCancel();
+    }
+    return;
+  }
+
+  if (state == NO_REMOTE_PROGRESS) {
+    if (mappedInput.wasPressed(MappedInputManager::Button::Confirm)) {
+      // Calculate hash if not done yet
+      if (documentHash.empty()) {
+        if (KOREADER_STORE.getMatchMethod() == DocumentMatchMethod::FILENAME) {
+          documentHash = KOReaderDocumentId::calculateFromFilename(epubPath);
+        } else {
+          documentHash = KOReaderDocumentId::calculate(epubPath);
+        }
+      }
+      performUpload();
+    }
+
+    if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
+      onCancel();
+    }
+    return;
+  }
+}
--- a/src/activities/reader/KOReaderSyncActivity.h
+++ b/src/activities/reader/KOReaderSyncActivity.h
@@ -0,0 +1,98 @@
+#pragma once
+#include <Epub.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+#include <memory>
+
+#include "KOReaderSyncClient.h"
+#include "ProgressMapper.h"
+#include "activities/ActivityWithSubactivity.h"
+
+/**
+ * Activity for syncing reading progress with KOReader sync server.
+ *
+ * Flow:
+ * 1. Connect to WiFi (if not connected)
+ * 2. Calculate document hash
+ * 3. Fetch remote progress
+ * 4. Show comparison and options (Apply/Upload/Cancel)
+ * 5. Apply or upload progress
+ */
+class KOReaderSyncActivity final : public ActivityWithSubactivity {
+ public:
+  using OnCancelCallback = std::function<void()>;
+  using OnSyncCompleteCallback = std::function<void(int newSpineIndex, int newPageNumber)>;
+
+  explicit KOReaderSyncActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
+                                const std::shared_ptr<Epub>& epub, const std::string& epubPath, int currentSpineIndex,
+                                int currentPage, int totalPagesInSpine, OnCancelCallback onCancel,
+                                OnSyncCompleteCallback onSyncComplete)
+      : ActivityWithSubactivity("KOReaderSync", renderer, mappedInput),
+        epub(epub),
+        epubPath(epubPath),
+        currentSpineIndex(currentSpineIndex),
+        currentPage(currentPage),
+        totalPagesInSpine(totalPagesInSpine),
+        remoteProgress{},
+        remotePosition{},
+        localProgress{},
+        onCancel(std::move(onCancel)),
+        onSyncComplete(std::move(onSyncComplete)) {}
+
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+  bool preventAutoSleep() override { return state == CONNECTING || state == SYNCING; }
+
+ private:
+  enum State {
+    WIFI_SELECTION,
+    CONNECTING,
+    SYNCING,
+    SHOWING_RESULT,
+    UPLOADING,
+    UPLOAD_COMPLETE,
+    NO_REMOTE_PROGRESS,
+    SYNC_FAILED,
+    NO_CREDENTIALS
+  };
+
+  std::shared_ptr<Epub> epub;
+  std::string epubPath;
+  int currentSpineIndex;
+  int currentPage;
+  int totalPagesInSpine;
+
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
+
+  State state = WIFI_SELECTION;
+  std::string statusMessage;
+  std::string documentHash;
+
+  // Remote progress data
+  bool hasRemoteProgress = false;
+  KOReaderProgress remoteProgress;
+  CrossPointPosition remotePosition;
+
+  // Local progress as KOReader format (for display)
+  KOReaderPosition localProgress;
+
+  // Selection in result screen (0=Apply, 1=Upload, 2=Cancel)
+  int selectedOption = 0;
+
+  OnCancelCallback onCancel;
+  OnSyncCompleteCallback onSyncComplete;
+
+  void onWifiSelectionComplete(bool success);
+  void performSync();
+  void performUpload();
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render();
+};
--- a/src/activities/settings/KOReaderAuthActivity.cpp
+++ b/src/activities/settings/KOReaderAuthActivity.cpp
@@ -0,0 +1,167 @@
+#include "KOReaderAuthActivity.h"
+
+#include <GfxRenderer.h>
+#include <WiFi.h>
+
+#include "KOReaderCredentialStore.h"
+#include "KOReaderSyncClient.h"
+#include "MappedInputManager.h"
+#include "activities/network/WifiSelectionActivity.h"
+#include "fontIds.h"
+
+void KOReaderAuthActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<KOReaderAuthActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void KOReaderAuthActivity::onWifiSelectionComplete(const bool success) {
+  exitActivity();
+
+  if (!success) {
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = FAILED;
+    errorMessage = "WiFi connection failed";
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = AUTHENTICATING;
+  statusMessage = "Authenticating...";
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+
+  performAuthentication();
+}
+
+void KOReaderAuthActivity::performAuthentication() {
+  const auto result = KOReaderSyncClient::authenticate();
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (result == KOReaderSyncClient::OK) {
+    state = SUCCESS;
+    statusMessage = "Successfully authenticated!";
+  } else {
+    state = FAILED;
+    errorMessage = KOReaderSyncClient::errorString(result);
+  }
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+}
+
+void KOReaderAuthActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
+  renderingMutex = xSemaphoreCreateMutex();
+
+  xTaskCreate(&KOReaderAuthActivity::taskTrampoline, "KOAuthTask",
+              4096,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+
+  // Turn on WiFi
+  WiFi.mode(WIFI_STA);
+
+  // Check if already connected
+  if (WiFi.status() == WL_CONNECTED) {
+    state = AUTHENTICATING;
+    statusMessage = "Authenticating...";
+    updateRequired = true;
+
+    // Perform authentication in a separate task
+    xTaskCreate(
+        [](void* param) {
+          auto* self = static_cast<KOReaderAuthActivity*>(param);
+          self->performAuthentication();
+          vTaskDelete(nullptr);
+        },
+        "AuthTask", 4096, this, 1, nullptr);
+    return;
+  }
+
+  // Launch WiFi selection
+  enterNewActivity(new WifiSelectionActivity(renderer, mappedInput,
+                                             [this](const bool connected) { onWifiSelectionComplete(connected); }));
+}
+
+void KOReaderAuthActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
+  // Turn off wifi
+  WiFi.disconnect(false);
+  delay(100);
+  WiFi.mode(WIFI_OFF);
+  delay(100);
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+}
+
+void KOReaderAuthActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired && !subActivity) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void KOReaderAuthActivity::render() {
+  if (subActivity) {
+    return;
+  }
+
+  renderer.clearScreen();
+  renderer.drawCenteredText(UI_12_FONT_ID, 15, "KOReader Auth", true, EpdFontFamily::BOLD);
+
+  if (state == AUTHENTICATING) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 300, statusMessage.c_str(), true, EpdFontFamily::BOLD);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == SUCCESS) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 280, "Success!", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_10_FONT_ID, 320, "KOReader sync is ready to use");
+
+    const auto labels = mappedInput.mapLabels("Done", "", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == FAILED) {
+    renderer.drawCenteredText(UI_10_FONT_ID, 280, "Authentication Failed", true, EpdFontFamily::BOLD);
+    renderer.drawCenteredText(UI_10_FONT_ID, 320, errorMessage.c_str());
+
+    const auto labels = mappedInput.mapLabels("Back", "", "", "");
+    renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+}
+
+void KOReaderAuthActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
+  if (state == SUCCESS || state == FAILED) {
+    if (mappedInput.wasPressed(MappedInputManager::Button::Back) ||
+        mappedInput.wasPressed(MappedInputManager::Button::Confirm)) {
+      onComplete();
+    }
+  }
+}
--- a/src/activities/settings/KOReaderAuthActivity.h
+++ b/src/activities/settings/KOReaderAuthActivity.h
@@ -0,0 +1,44 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+
+#include "activities/ActivityWithSubactivity.h"
+
+/**
+ * Activity for testing KOReader credentials.
+ * Connects to WiFi and authenticates with the KOReader sync server.
+ */
+class KOReaderAuthActivity final : public ActivityWithSubactivity {
+ public:
+  explicit KOReaderAuthActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
+                                const std::function<void()>& onComplete)
+      : ActivityWithSubactivity("KOReaderAuth", renderer, mappedInput), onComplete(onComplete) {}
+
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+  bool preventAutoSleep() override { return state == CONNECTING || state == AUTHENTICATING; }
+
+ private:
+  enum State { WIFI_SELECTION, CONNECTING, AUTHENTICATING, SUCCESS, FAILED };
+
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
+
+  State state = WIFI_SELECTION;
+  std::string statusMessage;
+  std::string errorMessage;
+
+  const std::function<void()> onComplete;
+
+  void onWifiSelectionComplete(bool success);
+  void performAuthentication();
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render();
+};
--- a/src/activities/settings/KOReaderSettingsActivity.cpp
+++ b/src/activities/settings/KOReaderSettingsActivity.cpp
@@ -0,0 +1,213 @@
+#include "KOReaderSettingsActivity.h"
+
+#include <GfxRenderer.h>
+
+#include <cstring>
+
+#include "KOReaderAuthActivity.h"
+#include "KOReaderCredentialStore.h"
+#include "MappedInputManager.h"
+#include "activities/util/KeyboardEntryActivity.h"
+#include "fontIds.h"
+
+namespace {
+constexpr int MENU_ITEMS = 5;
+const char* menuNames[MENU_ITEMS] = {"Username", "Password", "Sync Server URL", "Document Matching", "Authenticate"};
+}  // namespace
+
+void KOReaderSettingsActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<KOReaderSettingsActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void KOReaderSettingsActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
+  renderingMutex = xSemaphoreCreateMutex();
+  selectedIndex = 0;
+  updateRequired = true;
+
+  xTaskCreate(&KOReaderSettingsActivity::taskTrampoline, "KOReaderSettingsTask",
+              4096,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+}
+
+void KOReaderSettingsActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+}
+
+void KOReaderSettingsActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
+  if (mappedInput.wasPressed(MappedInputManager::Button::Back)) {
+    onBack();
+    return;
+  }
+
+  if (mappedInput.wasPressed(MappedInputManager::Button::Confirm)) {
+    handleSelection();
+    return;
+  }
+
+  if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
+      mappedInput.wasPressed(MappedInputManager::Button::Left)) {
+    selectedIndex = (selectedIndex + MENU_ITEMS - 1) % MENU_ITEMS;
+    updateRequired = true;
+  } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
+             mappedInput.wasPressed(MappedInputManager::Button::Right)) {
+    selectedIndex = (selectedIndex + 1) % MENU_ITEMS;
+    updateRequired = true;
+  }
+}
+
+void KOReaderSettingsActivity::handleSelection() {
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+
+  if (selectedIndex == 0) {
+    // Username
+    exitActivity();
+    enterNewActivity(new KeyboardEntryActivity(
+        renderer, mappedInput, "KOReader Username", KOREADER_STORE.getUsername(), 10,
+        64,     // maxLength
+        false,  // not password
+        [this](const std::string& username) {
+          KOREADER_STORE.setCredentials(username, KOREADER_STORE.getPassword());
+          KOREADER_STORE.saveToFile();
+          exitActivity();
+          updateRequired = true;
+        },
+        [this]() {
+          exitActivity();
+          updateRequired = true;
+        }));
+  } else if (selectedIndex == 1) {
+    // Password
+    exitActivity();
+    enterNewActivity(new KeyboardEntryActivity(
+        renderer, mappedInput, "KOReader Password", KOREADER_STORE.getPassword(), 10,
+        64,     // maxLength
+        false,  // show characters
+        [this](const std::string& password) {
+          KOREADER_STORE.setCredentials(KOREADER_STORE.getUsername(), password);
+          KOREADER_STORE.saveToFile();
+          exitActivity();
+          updateRequired = true;
+        },
+        [this]() {
+          exitActivity();
+          updateRequired = true;
+        }));
+  } else if (selectedIndex == 2) {
+    // Sync Server URL - prefill with https:// if empty to save typing
+    const std::string currentUrl = KOREADER_STORE.getServerUrl();
+    const std::string prefillUrl = currentUrl.empty() ? "https://" : currentUrl;
+    exitActivity();
+    enterNewActivity(new KeyboardEntryActivity(
+        renderer, mappedInput, "Sync Server URL", prefillUrl, 10,
+        128,    // maxLength - URLs can be long
+        false,  // not password
+        [this](const std::string& url) {
+          // Clear if user just left the prefilled https://
+          const std::string urlToSave = (url == "https://" || url == "http://") ? "" : url;
+          KOREADER_STORE.setServerUrl(urlToSave);
+          KOREADER_STORE.saveToFile();
+          exitActivity();
+          updateRequired = true;
+        },
+        [this]() {
+          exitActivity();
+          updateRequired = true;
+        }));
+  } else if (selectedIndex == 3) {
+    // Document Matching - toggle between Filename and Binary
+    const auto current = KOREADER_STORE.getMatchMethod();
+    const auto newMethod =
+        (current == DocumentMatchMethod::FILENAME) ? DocumentMatchMethod::BINARY : DocumentMatchMethod::FILENAME;
+    KOREADER_STORE.setMatchMethod(newMethod);
+    KOREADER_STORE.saveToFile();
+    updateRequired = true;
+  } else if (selectedIndex == 4) {
+    // Authenticate
+    if (!KOREADER_STORE.hasCredentials()) {
+      // Can't authenticate without credentials - just show message briefly
+      xSemaphoreGive(renderingMutex);
+      return;
+    }
+    exitActivity();
+    enterNewActivity(new KOReaderAuthActivity(renderer, mappedInput, [this] {
+      exitActivity();
+      updateRequired = true;
+    }));
+  }
+
+  xSemaphoreGive(renderingMutex);
+}
+
+void KOReaderSettingsActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired && !subActivity) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void KOReaderSettingsActivity::render() {
+  renderer.clearScreen();
+
+  const auto pageWidth = renderer.getScreenWidth();
+
+  // Draw header
+  renderer.drawCenteredText(UI_12_FONT_ID, 15, "KOReader Sync", true, EpdFontFamily::BOLD);
+
+  // Draw selection highlight
+  renderer.fillRect(0, 60 + selectedIndex * 30 - 2, pageWidth - 1, 30);
+
+  // Draw menu items
+  for (int i = 0; i < MENU_ITEMS; i++) {
+    const int settingY = 60 + i * 30;
+    const bool isSelected = (i == selectedIndex);
+
+    renderer.drawText(UI_10_FONT_ID, 20, settingY, menuNames[i], !isSelected);
+
+    // Draw status for each item
+    const char* status = "";
+    if (i == 0) {
+      status = KOREADER_STORE.getUsername().empty() ? "[Not Set]" : "[Set]";
+    } else if (i == 1) {
+      status = KOREADER_STORE.getPassword().empty() ? "[Not Set]" : "[Set]";
+    } else if (i == 2) {
+      status = KOREADER_STORE.getServerUrl().empty() ? "[Not Set]" : "[Set]";
+    } else if (i == 3) {
+      status = KOREADER_STORE.getMatchMethod() == DocumentMatchMethod::FILENAME ? "[Filename]" : "[Binary]";
+    } else if (i == 4) {
+      status = KOREADER_STORE.hasCredentials() ? "" : "[Set credentials first]";
+    }
+
+    const auto width = renderer.getTextWidth(UI_10_FONT_ID, status);
+    renderer.drawText(UI_10_FONT_ID, pageWidth - 20 - width, settingY, status, !isSelected);
+  }
+
+  // Draw button hints
+  const auto labels = mappedInput.mapLabels("« Back", "Select", "", "");
+  renderer.drawButtonHints(UI_10_FONT_ID, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+
+  renderer.displayBuffer();
+}
--- a/src/activities/settings/KOReaderSettingsActivity.h
+++ b/src/activities/settings/KOReaderSettingsActivity.h
@@ -0,0 +1,36 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+
+#include "activities/ActivityWithSubactivity.h"
+
+/**
+ * Submenu for KOReader Sync settings.
+ * Shows username, password, and authenticate options.
+ */
+class KOReaderSettingsActivity final : public ActivityWithSubactivity {
+ public:
+  explicit KOReaderSettingsActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
+                                    const std::function<void()>& onBack)
+      : ActivityWithSubactivity("KOReaderSettings", renderer, mappedInput), onBack(onBack) {}
+
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+
+ private:
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
+
+  int selectedIndex = 0;
+  const std::function<void()> onBack;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render();
+  void handleSelection();
+};
--- a/src/activities/settings/SettingsActivity.cpp
+++ b/src/activities/settings/SettingsActivity.cpp
@@ -7,13 +7,14 @@

 #include "CalibreSettingsActivity.h"
 #include "CrossPointSettings.h"
+#include "KOReaderSettingsActivity.h"
 #include "MappedInputManager.h"
 #include "OtaUpdateActivity.h"
 #include "fontIds.h"

 // Define the static settings list
 namespace {
-constexpr int settingsCount = 20;
+constexpr int settingsCount = 21;
 const SettingInfo settingsList[settingsCount] = {
    // Should match with SLEEP_SCREEN_MODE
    SettingInfo::Enum("Sleep Screen", &CrossPointSettings::sleepScreen, {"Dark", "Light", "Custom", "Cover", "None"}),
@@ -41,6 +42,7 @@ const SettingInfo settingsList[settingsCount] = {
                      {"1 min", "5 min", "10 min", "15 min", "30 min"}),
    SettingInfo::Enum("Refresh Frequency", &CrossPointSettings::refreshFrequency,
                      {"1 page", "5 pages", "10 pages", "15 pages", "30 pages"}),
+    SettingInfo::Action("KOReader Sync"),
    SettingInfo::Action("Calibre Settings"),
    SettingInfo::Action("Check for updates")};
 }  // namespace
@@ -115,7 +117,6 @@ void SettingsActivity::loop() {
 }

 void SettingsActivity::toggleCurrentSetting() {
-  // Validate index
  if (selectedSettingIndex < 0 || selectedSettingIndex >= settingsCount) {
    return;
  }
@@ -139,7 +140,15 @@ void SettingsActivity::toggleCurrentSetting() {
      SETTINGS.*(setting.valuePtr) = currentValue + setting.valueRange.step;
    }
  } else if (setting.type == SettingType::ACTION) {
-    if (strcmp(setting.name, "Calibre Settings") == 0) {
+    if (strcmp(setting.name, "KOReader Sync") == 0) {
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      exitActivity();
+      enterNewActivity(new KOReaderSettingsActivity(renderer, mappedInput, [this] {
+        exitActivity();
+        updateRequired = true;
+      }));
+      xSemaphoreGive(renderingMutex);
+    } else if (strcmp(setting.name, "Calibre Settings") == 0) {
      xSemaphoreTake(renderingMutex, portMAX_DELAY);
      exitActivity();
      enterNewActivity(new CalibreSettingsActivity(renderer, mappedInput, [this] {
@@ -186,18 +195,19 @@ void SettingsActivity::render() const {
  // Draw header
  renderer.drawCenteredText(UI_12_FONT_ID, 15, "Settings", true, EpdFontFamily::BOLD);

-  // Draw selection
+  // Draw selection highlight
  renderer.fillRect(0, 60 + selectedSettingIndex * 30 - 2, pageWidth - 1, 30);

  // Draw all settings
  for (int i = 0; i < settingsCount; i++) {
    const int settingY = 60 + i * 30;  // 30 pixels between settings
+    const bool isSelected = (i == selectedSettingIndex);

    // Draw setting name
-    renderer.drawText(UI_10_FONT_ID, 20, settingY, settingsList[i].name, i != selectedSettingIndex);
+    renderer.drawText(UI_10_FONT_ID, 20, settingY, settingsList[i].name, !isSelected);

    // Draw value based on setting type
-    std::string valueText = "";
+    std::string valueText;
    if (settingsList[i].type == SettingType::TOGGLE && settingsList[i].valuePtr != nullptr) {
      const bool value = SETTINGS.*(settingsList[i].valuePtr);
      valueText = value ? "ON" : "OFF";
@@ -207,8 +217,10 @@ void SettingsActivity::render() const {
    } else if (settingsList[i].type == SettingType::VALUE && settingsList[i].valuePtr != nullptr) {
      valueText = std::to_string(SETTINGS.*(settingsList[i].valuePtr));
    }
-    const auto width = renderer.getTextWidth(UI_10_FONT_ID, valueText.c_str());
-    renderer.drawText(UI_10_FONT_ID, pageWidth - 20 - width, settingY, valueText.c_str(), i != selectedSettingIndex);
+    if (!valueText.empty()) {
+      const auto width = renderer.getTextWidth(UI_10_FONT_ID, valueText.c_str());
+      renderer.drawText(UI_10_FONT_ID, pageWidth - 20 - width, settingY, valueText.c_str(), !isSelected);
+    }
  }

  // Draw version text above button hints