fixes wake from sleep being randomly not reliable

.gitignore

@@ -9,3 +9,4 @@ build
 **/__pycache__/
 /compile_commands.json
 /.cache
+notes.md

lib/GfxRenderer/GfxRenderer.cpp

@@ -8,6 +8,11 @@ void GfxRenderer::begin() {
     Serial.printf("[%lu] [GFX] !! No framebuffer\n", millis());
     assert(false);
   }
+  panelWidth = display.getDisplayWidth();
+  panelHeight = display.getDisplayHeight();
+  panelWidthBytes = display.getDisplayWidthBytes();
+  frameBufferSize = display.getBufferSize();
+  bwBufferChunks.assign((frameBufferSize + BW_BUFFER_CHUNK_SIZE - 1) / BW_BUFFER_CHUNK_SIZE, nullptr);
 }
 
 void GfxRenderer::insertFont(const int fontId, EpdFontFamily font) { fontMap.insert({fontId, font}); }
@@ -15,25 +20,25 @@ void GfxRenderer::insertFont(const int fontId, EpdFontFamily font) { fontMap.ins
 // Translate logical (x,y) coordinates to physical panel coordinates based on current orientation
 // This should always be inlined for better performance
 static inline void rotateCoordinates(const GfxRenderer::Orientation orientation, const int x, const int y, int* phyX,
-                                     int* phyY) {
+                                     int* phyY, const uint16_t panelWidth, const uint16_t panelHeight) {
   switch (orientation) {
     case GfxRenderer::Portrait: {
       // Logical portrait (480x800) → panel (800x480)
       // Rotation: 90 degrees clockwise
       *phyX = y;
-      *phyY = HalDisplay::DISPLAY_HEIGHT - 1 - x;
+      *phyY = panelHeight - 1 - x;
       break;
     }
     case GfxRenderer::LandscapeClockwise: {
       // Logical landscape (800x480) rotated 180 degrees (swap top/bottom and left/right)
-      *phyX = HalDisplay::DISPLAY_WIDTH - 1 - x;
-      *phyY = HalDisplay::DISPLAY_HEIGHT - 1 - y;
+      *phyX = panelWidth - 1 - x;
+      *phyY = panelHeight - 1 - y;
       break;
     }
     case GfxRenderer::PortraitInverted: {
       // Logical portrait (480x800) → panel (800x480)
       // Rotation: 90 degrees counter-clockwise
-      *phyX = HalDisplay::DISPLAY_WIDTH - 1 - y;
+      *phyX = panelWidth - 1 - y;
       *phyY = x;
       break;
     }
@@ -53,16 +58,16 @@ void GfxRenderer::drawPixel(const int x, const int y, const bool state) const {
   int phyY = 0;
 
   // Note: this call should be inlined for better performance
-  rotateCoordinates(orientation, x, y, &phyX, &phyY);
+  rotateCoordinates(orientation, x, y, &phyX, &phyY, panelWidth, panelHeight);
 
   // Bounds checking against physical panel dimensions
-  if (phyX < 0 || phyX >= HalDisplay::DISPLAY_WIDTH || phyY < 0 || phyY >= HalDisplay::DISPLAY_HEIGHT) {
+  if (phyX < 0 || phyX >= panelWidth || phyY < 0 || phyY >= panelHeight) {
     Serial.printf("[%lu] [GFX] !! Outside range (%d, %d) -> (%d, %d)\n", millis(), x, y, phyX, phyY);
     return;
   }
 
   // Calculate byte position and bit position
-  const uint16_t byteIndex = phyY * HalDisplay::DISPLAY_WIDTH_BYTES + (phyX / 8);
+  const uint32_t byteIndex = static_cast<uint32_t>(phyY) * panelWidthBytes + (phyX / 8);
   const uint8_t bitPosition = 7 - (phyX % 8);  // MSB first
 
   if (state) {
@@ -383,7 +388,7 @@ void GfxRenderer::fillRoundedRect(const int x, const int y, const int width, con
 void GfxRenderer::drawImage(const uint8_t bitmap[], const int x, const int y, const int width, const int height) const {
   int rotatedX = 0;
   int rotatedY = 0;
-  rotateCoordinates(orientation, x, y, &rotatedX, &rotatedY);
+  rotateCoordinates(orientation, x, y, &rotatedX, &rotatedY, panelWidth, panelHeight);
   // Rotate origin corner
   switch (orientation) {
     case Portrait:
@@ -648,7 +653,7 @@ void GfxRenderer::clearScreen(const uint8_t color) const {
 }
 
 void GfxRenderer::invertScreen() const {
-  for (int i = 0; i < HalDisplay::BUFFER_SIZE; i++) {
+  for (uint32_t i = 0; i < frameBufferSize; i++) {
     frameBuffer[i] = ~frameBuffer[i];
   }
 }
@@ -684,13 +689,13 @@ int GfxRenderer::getScreenWidth() const {
     case Portrait:
     case PortraitInverted:
       // 480px wide in portrait logical coordinates
-      return HalDisplay::DISPLAY_HEIGHT;
+      return panelHeight;
     case LandscapeClockwise:
     case LandscapeCounterClockwise:
       // 800px wide in landscape logical coordinates
-      return HalDisplay::DISPLAY_WIDTH;
+      return panelWidth;
   }
-  return HalDisplay::DISPLAY_HEIGHT;
+  return panelHeight;
 }
 
 int GfxRenderer::getScreenHeight() const {
@@ -698,13 +703,13 @@ int GfxRenderer::getScreenHeight() const {
     case Portrait:
     case PortraitInverted:
       // 800px tall in portrait logical coordinates
-      return HalDisplay::DISPLAY_WIDTH;
+      return panelWidth;
     case LandscapeClockwise:
     case LandscapeCounterClockwise:
       // 480px tall in landscape logical coordinates
-      return HalDisplay::DISPLAY_HEIGHT;
+      return panelHeight;
   }
-  return HalDisplay::DISPLAY_WIDTH;
+  return panelWidth;
 }
 
 int GfxRenderer::getSpaceWidth(const int fontId) const {
@@ -841,7 +846,7 @@ void GfxRenderer::drawTextRotated90CW(const int fontId, const int x, const int y
 
 uint8_t* GfxRenderer::getFrameBuffer() const { return frameBuffer; }
 
-size_t GfxRenderer::getBufferSize() { return HalDisplay::BUFFER_SIZE; }
+size_t GfxRenderer::getBufferSize() { return EInkDisplay::MAX_BUFFER_SIZE; }
 
 // unused
 // void GfxRenderer::grayscaleRevert() const { display.grayscaleRevert(); }
@@ -869,7 +874,7 @@ void GfxRenderer::freeBwBufferChunks() {
  */
 bool GfxRenderer::storeBwBuffer() {
   // Allocate and copy each chunk
-  for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
+  for (size_t i = 0; i < bwBufferChunks.size(); i++) {
     // Check if any chunks are already allocated
     if (bwBufferChunks[i]) {
       Serial.printf("[%lu] [GFX] !! BW buffer chunk %zu already stored - this is likely a bug, freeing chunk\n",
@@ -879,20 +884,20 @@ bool GfxRenderer::storeBwBuffer() {
     }
 
     const size_t offset = i * BW_BUFFER_CHUNK_SIZE;
-    bwBufferChunks[i] = static_cast<uint8_t*>(malloc(BW_BUFFER_CHUNK_SIZE));
+    const size_t chunkSize = std::min(BW_BUFFER_CHUNK_SIZE, static_cast<size_t>(frameBufferSize - offset));
+    bwBufferChunks[i] = static_cast<uint8_t*>(malloc(chunkSize));
 
     if (!bwBufferChunks[i]) {
-      Serial.printf("[%lu] [GFX] !! Failed to allocate BW buffer chunk %zu (%zu bytes)\n", millis(), i,
-                    BW_BUFFER_CHUNK_SIZE);
+      Serial.printf("[%lu] [GFX] !! Failed to allocate BW buffer chunk %zu (%zu bytes)\n", millis(), i, chunkSize);
       // Free previously allocated chunks
       freeBwBufferChunks();
       return false;
     }
 
-    memcpy(bwBufferChunks[i], frameBuffer + offset, BW_BUFFER_CHUNK_SIZE);
+    memcpy(bwBufferChunks[i], frameBuffer + offset, chunkSize);
   }
 
-  Serial.printf("[%lu] [GFX] Stored BW buffer in %zu chunks (%zu bytes each)\n", millis(), BW_BUFFER_NUM_CHUNKS,
+  Serial.printf("[%lu] [GFX] Stored BW buffer in %zu chunks (%zu bytes each)\n", millis(), bwBufferChunks.size(),
                 BW_BUFFER_CHUNK_SIZE);
   return true;
 }
@@ -917,7 +922,7 @@ void GfxRenderer::restoreBwBuffer() {
     return;
   }
 
-  for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
+  for (size_t i = 0; i < bwBufferChunks.size(); i++) {
     // Check if chunk is missing
     if (!bwBufferChunks[i]) {
       Serial.printf("[%lu] [GFX] !! BW buffer chunks not stored - this is likely a bug\n", millis());
@@ -926,7 +931,8 @@ void GfxRenderer::restoreBwBuffer() {
     }
 
     const size_t offset = i * BW_BUFFER_CHUNK_SIZE;
-    memcpy(frameBuffer + offset, bwBufferChunks[i], BW_BUFFER_CHUNK_SIZE);
+    const size_t chunkSize = std::min(BW_BUFFER_CHUNK_SIZE, static_cast<size_t>(frameBufferSize - offset));
+    memcpy(frameBuffer + offset, bwBufferChunks[i], chunkSize);
   }
 
   display.cleanupGrayscaleBuffers(frameBuffer);

lib/GfxRenderer/GfxRenderer.h

@@ -4,6 +4,7 @@
 #include <HalDisplay.h>
 
 #include <map>
+#include <vector>
 
 #include "Bitmap.h"
 
@@ -25,16 +26,17 @@ class GfxRenderer {
 
  private:
   static constexpr size_t BW_BUFFER_CHUNK_SIZE = 8000;  // 8KB chunks to allow for non-contiguous memory
-  static constexpr size_t BW_BUFFER_NUM_CHUNKS = HalDisplay::BUFFER_SIZE / BW_BUFFER_CHUNK_SIZE;
-  static_assert(BW_BUFFER_CHUNK_SIZE * BW_BUFFER_NUM_CHUNKS == HalDisplay::BUFFER_SIZE,
-                "BW buffer chunking does not line up with display buffer size");
 
   HalDisplay& display;
   RenderMode renderMode;
   Orientation orientation;
   bool fadingFix;
   uint8_t* frameBuffer = nullptr;
-  uint8_t* bwBufferChunks[BW_BUFFER_NUM_CHUNKS] = {nullptr};
+  uint16_t panelWidth = HalDisplay::DISPLAY_WIDTH;
+  uint16_t panelHeight = HalDisplay::DISPLAY_HEIGHT;
+  uint16_t panelWidthBytes = HalDisplay::DISPLAY_WIDTH_BYTES;
+  uint32_t frameBufferSize = HalDisplay::BUFFER_SIZE;
+  std::vector<uint8_t*> bwBufferChunks;
   std::map<int, EpdFontFamily> fontMap;
   void renderChar(const EpdFontFamily& fontFamily, uint32_t cp, int* x, const int* y, bool pixelState,
                   EpdFontFamily::Style style) const;
@@ -68,6 +70,7 @@ class GfxRenderer {
   // Screen ops
   int getScreenWidth() const;
   int getScreenHeight() const;
+  void requestResync(uint8_t settlePasses = 0) const { display.requestResync(settlePasses); }
   void displayBuffer(HalDisplay::RefreshMode refreshMode = HalDisplay::FAST_REFRESH) const;
   // EXPERIMENTAL: Windowed update - display only a rectangular region
   // void displayWindow(int x, int y, int width, int height) const;

lib/hal/HalDisplay.cpp

@@ -9,6 +9,8 @@ HalDisplay::~HalDisplay() {}
 
 void HalDisplay::begin() { einkDisplay.begin(); }
 
+void HalDisplay::setDisplayDimensions(uint16_t width, uint16_t height) { einkDisplay.setDisplayDimensions(width, height); }
+
 void HalDisplay::clearScreen(uint8_t color) const { einkDisplay.clearScreen(color); }
 
 void HalDisplay::drawImage(const uint8_t* imageData, uint16_t x, uint16_t y, uint16_t w, uint16_t h,
@@ -36,6 +38,8 @@ void HalDisplay::refreshDisplay(HalDisplay::RefreshMode mode, bool turnOffScreen
   einkDisplay.refreshDisplay(convertRefreshMode(mode), turnOffScreen);
 }
 
+void HalDisplay::requestResync(uint8_t settlePasses) { einkDisplay.requestResync(settlePasses); }
+
 void HalDisplay::deepSleep() { einkDisplay.deepSleep(); }
 
 uint8_t* HalDisplay::getFrameBuffer() const { return einkDisplay.getFrameBuffer(); }
@@ -51,3 +55,11 @@ void HalDisplay::copyGrayscaleMsbBuffers(const uint8_t* msbBuffer) { einkDisplay
 void HalDisplay::cleanupGrayscaleBuffers(const uint8_t* bwBuffer) { einkDisplay.cleanupGrayscaleBuffers(bwBuffer); }
 
 void HalDisplay::displayGrayBuffer(bool turnOffScreen) { einkDisplay.displayGrayBuffer(turnOffScreen); }
+
+uint16_t HalDisplay::getDisplayWidth() const { return einkDisplay.getDisplayWidth(); }
+
+uint16_t HalDisplay::getDisplayHeight() const { return einkDisplay.getDisplayHeight(); }
+
+uint16_t HalDisplay::getDisplayWidthBytes() const { return einkDisplay.getDisplayWidthBytes(); }
+
+uint32_t HalDisplay::getBufferSize() const { return einkDisplay.getBufferSize(); }

lib/hal/HalDisplay.h

@@ -20,6 +20,9 @@ class HalDisplay {
   // Initialize the display hardware and driver
   void begin();
 
+  // Pre-begin display config passthroughs (used by X3 setup path)
+  void setDisplayDimensions(uint16_t width, uint16_t height);
+
   // Display dimensions
   static constexpr uint16_t DISPLAY_WIDTH = EInkDisplay::DISPLAY_WIDTH;
   static constexpr uint16_t DISPLAY_HEIGHT = EInkDisplay::DISPLAY_HEIGHT;
@@ -33,6 +36,9 @@ class HalDisplay {
 
   void displayBuffer(RefreshMode mode = RefreshMode::FAST_REFRESH, bool turnOffScreen = false);
   void refreshDisplay(RefreshMode mode = RefreshMode::FAST_REFRESH, bool turnOffScreen = false);
+  // Hint the display driver to perform a one-shot full resync on next update.
+  // Optional settle passes are used by X3 only.
+  void requestResync(uint8_t settlePasses = 0);
 
   // Power management
   void deepSleep();
@@ -47,6 +53,12 @@ class HalDisplay {
 
   void displayGrayBuffer(bool turnOffScreen = false);
 
+  // Runtime geometry passthrough
+  uint16_t getDisplayWidth() const;
+  uint16_t getDisplayHeight() const;
+  uint16_t getDisplayWidthBytes() const;
+  uint32_t getBufferSize() const;
+
  private:
   EInkDisplay einkDisplay;
 };

lib/hal/HalGPIO.cpp

@@ -5,7 +5,14 @@
 void HalGPIO::begin() {
   inputMgr.begin();
   SPI.begin(EPD_SCLK, SPI_MISO, EPD_MOSI, EPD_CS);
-  pinMode(BAT_GPIO0, INPUT);
+
+  // X3 boards bias GPIO4 (EPD DC) around ~700 ADC counts at boot in our setup.
+  // X4 boards do not, and use GPIO0 for battery ADC.
+  _detectAdcValue = analogRead(4);
+  _deviceType = (_detectAdcValue > 500 && _detectAdcValue < 1200) ? DeviceType::X3 : DeviceType::X4;
+  _batteryPin = (_deviceType == DeviceType::X3) ? 4 : BAT_GPIO0;
+
+  pinMode(_batteryPin, INPUT);
   pinMode(UART0_RXD, INPUT);
 }
 
@@ -36,8 +43,11 @@ void HalGPIO::startDeepSleep() {
 }
 
 int HalGPIO::getBatteryPercentage() const {
-  static const BatteryMonitor battery = BatteryMonitor(BAT_GPIO0);
-  return battery.readPercentage();
+  if (_deviceType == DeviceType::X3) {
+    return 0;
+  }
+  static const BatteryMonitor bat(BAT_GPIO0);
+  return bat.readPercentage();
 }
 
 bool HalGPIO::isUsbConnected() const {
@@ -61,4 +71,4 @@ HalGPIO::WakeupReason HalGPIO::getWakeupReason() const {
     return WakeupReason::AfterUSBPower;
   }
   return WakeupReason::Other;
-}
+}

lib/hal/HalGPIO.h

@@ -23,6 +23,14 @@ class HalGPIO {
   InputManager inputMgr;
 #endif
 
+ public:
+  enum class DeviceType : uint8_t { X4, X3 };
+
+ private:
+  DeviceType _deviceType = DeviceType::X4;
+  int _detectAdcValue = 0;
+  int _batteryPin = BAT_GPIO0;
+
  public:
   HalGPIO() = default;
 
@@ -47,6 +55,11 @@ class HalGPIO {
   // Check if USB is connected
   bool isUsbConnected() const;
 
+  // Device detection helpers
+  DeviceType getDeviceType() const { return _deviceType; }
+  int getDetectAdcValue() const { return _detectAdcValue; }
+  int getBatteryPin() const { return _batteryPin; }
+
   enum class WakeupReason { PowerButton, AfterFlash, AfterUSBPower, Other };
 
   WakeupReason getWakeupReason() const;

src/Battery.cpp

@@ -0,0 +1,33 @@
+#include "Battery.h"
+#include <Wire.h>
+
+void BatteryProvider::setI2CFuelGauge(uint8_t i2cAddr, uint8_t socRegister) {
+  _useI2C = true;
+  _i2cAddr = i2cAddr;
+  _socRegister = socRegister;
+}
+
+uint16_t BatteryProvider::readPercentage() const {
+  if (_useI2C) {
+    // Read SOC directly from I2C fuel gauge (16-bit LE register).
+    // Returns 0 on I2C error so the UI shows 0% rather than crashing.
+    Wire.beginTransmission(_i2cAddr);
+    Wire.write(_socRegister);
+    if (Wire.endTransmission(false) != 0) return 0;
+    Wire.requestFrom(_i2cAddr, (uint8_t)2);
+    if (Wire.available() < 2) return 0;
+    const uint8_t lo = Wire.read();
+    const uint8_t hi = Wire.read();
+    const uint16_t soc = (hi << 8) | lo;
+    return soc > 100 ? 100 : soc;
+  }
+  // ADC path: read raw voltage, apply divider, convert via LiPo polynomial
+  return _adcMonitor.readPercentage();
+}
+
+// Meyer's singleton — single shared instance across all translation units.
+// Defaults to X4 ADC mode. For X3, main.cpp calls setI2CFuelGauge() to switch.
+BatteryProvider& battery() {
+  static BatteryProvider instance;
+  return instance;
+}

src/Battery.h

@@ -1,6 +1,29 @@
 #pragma once
 #include <BatteryMonitor.h>
+#include <cstdint>
 
-#define BAT_GPIO0 0  // Battery voltage
+#define BAT_GPIO0 0  // Battery voltage (X4 ADC pin)
 
-static BatteryMonitor battery(BAT_GPIO0);
+// Unified battery reader supporting two backends:
+//   - X4: ADC voltage divider on GPIO0 (default, no setup needed)
+//   - X3: BQ27220 fuel gauge via I2C at 0x55, SOC register 0x2C
+//         (call setI2CFuelGauge() after Wire.begin())
+class BatteryProvider {
+ public:
+  // Read battery percentage (0-100). Delegates to ADC or I2C depending on mode.
+  uint16_t readPercentage() const;
+
+  // Switch to I2C fuel gauge mode. Wire.begin() must be called first.
+  // i2cAddr: fuel gauge I2C address (e.g. 0x55 for BQ27220)
+  // socRegister: register holding state-of-charge 0-100% (e.g. 0x2C)
+  void setI2CFuelGauge(uint8_t i2cAddr, uint8_t socRegister);
+
+ private:
+  BatteryMonitor _adcMonitor{BAT_GPIO0};
+  bool _useI2C = false;
+  uint8_t _i2cAddr = 0;
+  uint8_t _socRegister = 0;
+};
+
+// Shared singleton used by themes and activities.
+BatteryProvider& battery();

src/activities/reader/EpubReaderActivity.cpp

@@ -33,6 +33,12 @@ int clampPercent(int percent) {
   return percent;
 }
 
+bool isX3DisplayGeometry(const GfxRenderer& renderer) {
+  const int w = renderer.getScreenWidth();
+  const int h = renderer.getScreenHeight();
+  return (w == 792 && h == 528) || (w == 528 && h == 792);
+}
+
 // Apply the logical reader orientation to the renderer.
 // This centralizes orientation mapping so we don't duplicate switch logic elsewhere.
 void applyReaderOrientation(GfxRenderer& renderer, const uint8_t orientation) {
@@ -682,12 +688,13 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
     pagesUntilFullRefresh--;
   }
 
-  // Save bw buffer to reset buffer state after grayscale data sync
-  renderer.storeBwBuffer();
+  const bool useGrayscaleAA = SETTINGS.textAntiAliasing && !isX3DisplayGeometry(renderer);
+  if (useGrayscaleAA) {
+    // Save BW buffer only when we actually run grayscale passes.
+    renderer.storeBwBuffer();
 
-  // grayscale rendering
-  // TODO: Only do this if font supports it
-  if (SETTINGS.textAntiAliasing) {
+    // grayscale rendering
+    // TODO: Only do this if font supports it
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
     page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
@@ -702,10 +709,10 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
     // display grayscale part
     renderer.displayGrayBuffer();
     renderer.setRenderMode(GfxRenderer::BW);
-  }
 
-  // restore the bw data
-  renderer.restoreBwBuffer();
+    // restore the bw data
+    renderer.restoreBwBuffer();
+  }
 }
 
 void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const int orientedMarginBottom,

src/activities/reader/ReaderActivity.cpp

@@ -1,5 +1,6 @@
 #include "ReaderActivity.h"
 
+#include <GfxRenderer.h>
 #include <HalStorage.h>
 
 #include "Epub.h"
@@ -83,6 +84,7 @@ void ReaderActivity::onGoToEpubReader(std::unique_ptr<Epub> epub) {
   const auto epubPath = epub->getPath();
   currentBookPath = epubPath;
   exitActivity();
+  renderer.requestResync(1);
   enterNewActivity(new EpubReaderActivity(
       renderer, mappedInput, std::move(epub), [this, epubPath] { goToLibrary(epubPath); }, [this] { onGoBack(); }));
 }
@@ -91,6 +93,7 @@ void ReaderActivity::onGoToXtcReader(std::unique_ptr<Xtc> xtc) {
   const auto xtcPath = xtc->getPath();
   currentBookPath = xtcPath;
   exitActivity();
+  renderer.requestResync(1);
   enterNewActivity(new XtcReaderActivity(
       renderer, mappedInput, std::move(xtc), [this, xtcPath] { goToLibrary(xtcPath); }, [this] { onGoBack(); }));
 }
@@ -99,6 +102,7 @@ void ReaderActivity::onGoToTxtReader(std::unique_ptr<Txt> txt) {
   const auto txtPath = txt->getPath();
   currentBookPath = txtPath;
   exitActivity();
+  renderer.requestResync(1);
   enterNewActivity(new TxtReaderActivity(
       renderer, mappedInput, std::move(txt), [this, txtPath] { goToLibrary(txtPath); }, [this] { onGoBack(); }));
 }

src/components/themes/BaseTheme.cpp

@@ -22,7 +22,7 @@ constexpr int homeMarginTop = 30;
 void BaseTheme::drawBattery(const GfxRenderer& renderer, Rect rect, const bool showPercentage) const {
   // Left aligned battery icon and percentage
   // TODO refactor this so the percentage doesnt change after we position it
-  const uint16_t percentage = battery.readPercentage();
+  const uint16_t percentage = battery().readPercentage();
   if (showPercentage) {
     const auto percentageText = std::to_string(percentage) + "%";
     renderer.drawText(SMALL_FONT_ID, rect.x + batteryPercentSpacing + BaseMetrics::values.batteryWidth, rect.y,
@@ -232,7 +232,7 @@ void BaseTheme::drawHeader(const GfxRenderer& renderer, Rect rect, const char* t
       SETTINGS.hideBatteryPercentage != CrossPointSettings::HIDE_BATTERY_PERCENTAGE::HIDE_ALWAYS;
   int batteryX = rect.x + rect.width - BaseMetrics::values.contentSidePadding - BaseMetrics::values.batteryWidth;
   if (showBatteryPercentage) {
-    const uint16_t percentage = battery.readPercentage();
+    const uint16_t percentage = battery().readPercentage();
     const auto percentageText = std::to_string(percentage) + "%";
     batteryX -= renderer.getTextWidth(SMALL_FONT_ID, percentageText.c_str());
   }

src/components/themes/lyra/LyraTheme.cpp

@@ -22,7 +22,7 @@ constexpr int topHintButtonY = 345;
 
 void LyraTheme::drawBattery(const GfxRenderer& renderer, Rect rect, const bool showPercentage) const {
   // Left aligned battery icon and percentage
-  const uint16_t percentage = battery.readPercentage();
+  const uint16_t percentage = battery().readPercentage();
   if (showPercentage) {
     const auto percentageText = std::to_string(percentage) + "%";
     renderer.drawText(SMALL_FONT_ID, rect.x + batteryPercentSpacing + LyraMetrics::values.batteryWidth, rect.y,
@@ -64,7 +64,7 @@ void LyraTheme::drawHeader(const GfxRenderer& renderer, Rect rect, const char* t
       SETTINGS.hideBatteryPercentage != CrossPointSettings::HIDE_BATTERY_PERCENTAGE::HIDE_ALWAYS;
   int batteryX = rect.x + rect.width - LyraMetrics::values.contentSidePadding - LyraMetrics::values.batteryWidth;
   if (showBatteryPercentage) {
-    const uint16_t percentage = battery.readPercentage();
+    const uint16_t percentage = battery().readPercentage();
     const auto percentageText = std::to_string(percentage) + "%";
     batteryX -= renderer.getTextWidth(SMALL_FONT_ID, percentageText.c_str());
   }

src/main.cpp

@@ -5,6 +5,7 @@
 #include <HalGPIO.h>
 #include <HalStorage.h>
 #include <SPI.h>
+#include <Wire.h>
 #include <builtinFonts/all.h>
 
 #include <cstring>
@@ -128,6 +129,12 @@ EpdFontFamily ui12FontFamily(&ui12RegularFont, &ui12BoldFont);
 unsigned long t1 = 0;
 unsigned long t2 = 0;
 
+inline void requestResyncIfX3(uint8_t settlePasses = 0) {
+  if (gpio.getDeviceType() == HalGPIO::DeviceType::X3) {
+    display.requestResync(settlePasses);
+  }
+}
+
 void exitActivity() {
   if (currentActivity) {
     currentActivity->onExit();
@@ -193,11 +200,49 @@ void waitForPowerRelease() {
   }
 }
 
+// X3 wake gate: avoid "timing lottery" from strict calibration logic,
+// but still require an intentional press (not a tap).
+bool verifyPowerButtonDurationX3() {
+  constexpr uint16_t detectWindowMs = 1200;  // time to detect an intentional wake press
+  constexpr uint16_t minHoldMs = 180;        // short, deliberate hold (blocks accidental taps)
+
+  const unsigned long start = millis();
+  bool sawPress = false;
+  unsigned long pressStart = 0;
+
+  // Stage 1: wait for the button state to settle and detect a press.
+  while (millis() - start < detectWindowMs) {
+    gpio.update();
+    if (gpio.isPressed(HalGPIO::BTN_POWER)) {
+      sawPress = true;
+      pressStart = millis();
+      break;
+    }
+    delay(10);
+  }
+
+  if (!sawPress) {
+    return false;
+  }
+
+  // Stage 2: require a short continuous hold.
+  while (millis() - pressStart < minHoldMs) {
+    gpio.update();
+    if (!gpio.isPressed(HalGPIO::BTN_POWER)) {
+      return false;
+    }
+    delay(10);
+  }
+
+  return true;
+}
+
 // Enter deep sleep mode
 void enterDeepSleep() {
   APP_STATE.lastSleepFromReader = currentActivity && currentActivity->isReaderActivity();
   APP_STATE.saveToFile();
   exitActivity();
+  requestResyncIfX3(0);
   enterNewActivity(new SleepActivity(renderer, mappedInputManager));
 
   display.deepSleep();
@@ -247,12 +292,26 @@ void onGoToBrowser() {
 }
 
 void onGoHome() {
+  const bool returningFromReader = currentActivity && currentActivity->isReaderActivity();
+  if (returningFromReader && (gpio.getDeviceType() == HalGPIO::DeviceType::X3)) {
+    // Force Home's first frame to run a full resync on X3.
+    // Avoid doing a blocking scrub refresh before activity transition.
+    display.requestResync(1);
+  }
   exitActivity();
   enterNewActivity(new HomeActivity(renderer, mappedInputManager, onGoToReader, onGoToMyLibrary, onGoToRecentBooks,
                                     onGoToSettings, onGoToFileTransfer, onGoToBrowser));
 }
 
 void setupDisplayAndFonts() {
+  if (gpio.getDeviceType() == HalGPIO::DeviceType::X3) {
+    display.setDisplayDimensions(792, 528);
+    // X3 has a BQ27220 fuel gauge on I2C (addr 0x55) instead of an ADC voltage
+    // divider. SOC (0-100%) is read directly from register 0x2C.
+    // I2C bus: SDA=GPIO20, SCL=GPIO0, 400kHz (matches stock X3 firmware).
+    Wire.begin(20, 0, 400000);
+    battery().setI2CFuelGauge(0x55, 0x2C);
+  }
   display.begin();
   renderer.begin();
   Serial.printf("[%lu] [   ] Display initialized\n", millis());
@@ -307,11 +366,21 @@ void setup() {
   UITheme::getInstance().reload();
   ButtonNavigator::setMappedInputManager(mappedInputManager);
 
-  switch (gpio.getWakeupReason()) {
+  const auto wakeupReason = gpio.getWakeupReason();
+  switch (wakeupReason) {
     case HalGPIO::WakeupReason::PowerButton:
-      // For normal wakeups, verify power button press duration
-      Serial.printf("[%lu] [   ] Verifying power button press duration\n", millis());
-      verifyPowerButtonDuration();
+      // X3 uses a relaxed fixed hold check to avoid strict timing behavior
+      // while still filtering accidental single-click wakes.
+      if (gpio.getDeviceType() == HalGPIO::DeviceType::X3) {
+        Serial.printf("[%lu] [   ] Verifying relaxed power-button wake on X3\n", millis());
+        if (!verifyPowerButtonDurationX3()) {
+          gpio.startDeepSleep();
+        }
+      } else {
+        // For non-X3 wakeups, keep existing verification behavior.
+        Serial.printf("[%lu] [   ] Verifying power button press duration\n", millis());
+        verifyPowerButtonDuration();
+      }
       break;
     case HalGPIO::WakeupReason::AfterUSBPower:
       // If USB power caused a cold boot, go back to sleep
@@ -329,6 +398,10 @@ void setup() {
   Serial.printf("[%lu] [   ] Starting CrossPoint version " CROSSPOINT_VERSION "\n", millis());
 
   setupDisplayAndFonts();
+  if (wakeupReason == HalGPIO::WakeupReason::PowerButton || wakeupReason == HalGPIO::WakeupReason::AfterFlash ||
+      wakeupReason == HalGPIO::WakeupReason::Other) {
+    requestResyncIfX3(0);
+  }
 
   exitActivity();
   enterNewActivity(new BootActivity(renderer, mappedInputManager));