diff --git a/src/activities/boot_sleep/BootActivity.cpp b/src/activities/boot_sleep/BootActivity.cpp
index 9e59ed59..174ffb7d 100644
--- a/src/activities/boot_sleep/BootActivity.cpp
+++ b/src/activities/boot_sleep/BootActivity.cpp
@@ -8,6 +8,7 @@
 
 void BootActivity::onEnter() {
   Activity::onEnter();
+  RenderLock lock(*this);
 
   const auto pageWidth = renderer.getScreenWidth();
   const auto pageHeight = renderer.getScreenHeight();
diff --git a/src/activities/home/BookInfoActivity.cpp b/src/activities/home/BookInfoActivity.cpp
index 1c82ec8b..7c883cc6 100644
--- a/src/activities/home/BookInfoActivity.cpp
+++ b/src/activities/home/BookInfoActivity.cpp
@@ -98,7 +98,10 @@ void BookInfoActivity::loadData() {
 
 void BookInfoActivity::onEnter() {
   Activity::onEnter();
-  renderLoading();
+  {
+    RenderLock lock(*this);
+    renderLoading();
+  }
   loadData();
   requestUpdate(true);
 }
diff --git a/src/activities/reader/EpubReaderActivity.cpp b/src/activities/reader/EpubReaderActivity.cpp
index 21ef9566..8bf48f9d 100644
--- a/src/activities/reader/EpubReaderActivity.cpp
+++ b/src/activities/reader/EpubReaderActivity.cpp
@@ -58,7 +58,10 @@ void EpubReaderActivity::onEnter() {
 
   // Configure screen orientation based on settings
   // NOTE: This affects layout math and must be applied before any render calls.
-  ReaderUtils::applyOrientation(renderer, SETTINGS.orientation);
+  {
+    RenderLock lock(*this);
+    ReaderUtils::applyOrientation(renderer, SETTINGS.orientation);
+  }
 
   epub->setupCacheDir();
 
@@ -107,7 +110,10 @@ void EpubReaderActivity::onExit() {
   Activity::onExit();
 
   // Reset orientation back to portrait for the rest of the UI
-  renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  {
+    RenderLock lock(*this);
+    renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  }
 
   APP_STATE.readerActivityLoadCount = 0;
   APP_STATE.saveToFile();
diff --git a/src/activities/reader/ReaderActivity.cpp b/src/activities/reader/ReaderActivity.cpp
index 3a19ea39..3f702ab8 100644
--- a/src/activities/reader/ReaderActivity.cpp
+++ b/src/activities/reader/ReaderActivity.cpp
@@ -125,9 +125,12 @@ void ReaderActivity::onEnter() {
   if (isImageFile(initialBookPath)) {
     onGoToBmpViewer(initialBookPath);
   } else if (isXtcFile(initialBookPath)) {
-    renderer.clearScreen();
-    renderer.drawCenteredText(UI_12_FONT_ID, 300, tr(STR_LOADING), true, EpdFontFamily::BOLD);
-    renderer.displayBuffer();
+    {
+      RenderLock lock(*this);
+      renderer.clearScreen();
+      renderer.drawCenteredText(UI_12_FONT_ID, 300, tr(STR_LOADING), true, EpdFontFamily::BOLD);
+      renderer.displayBuffer();
+    }
 
     auto xtc = loadXtc(initialBookPath);
     if (!xtc) {
diff --git a/src/activities/reader/TxtReaderActivity.cpp b/src/activities/reader/TxtReaderActivity.cpp
index bef5ffaf..b328a7dc 100644
--- a/src/activities/reader/TxtReaderActivity.cpp
+++ b/src/activities/reader/TxtReaderActivity.cpp
@@ -92,7 +92,10 @@ void TxtReaderActivity::onEnter() {
     return;
   }
 
-  ReaderUtils::applyOrientation(renderer, SETTINGS.orientation);
+  {
+    RenderLock lock(*this);
+    ReaderUtils::applyOrientation(renderer, SETTINGS.orientation);
+  }
 
   txt->setupCacheDir();
 
@@ -111,7 +114,10 @@ void TxtReaderActivity::onExit() {
   Activity::onExit();
 
   // Reset orientation back to portrait for the rest of the UI
-  renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  {
+    RenderLock lock(*this);
+    renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  }
 
   pageOffsets.clear();
   currentPageLines.clear();
diff --git a/src/activities/util/BmpViewerActivity.cpp b/src/activities/util/BmpViewerActivity.cpp
index 38ea7f9c..54c4d60d 100644
--- a/src/activities/util/BmpViewerActivity.cpp
+++ b/src/activities/util/BmpViewerActivity.cpp
@@ -127,6 +127,7 @@ void BmpViewerActivity::onExit() {
 }
 
 bool BmpViewerActivity::renderBmpImage(const bool showControls) {
+  RenderLock lock(*this);
   FsFile file;
   const auto pageWidth = renderer.getScreenWidth();
   const auto pageHeight = renderer.getScreenHeight();
@@ -192,6 +193,7 @@ bool BmpViewerActivity::renderBmpImage(const bool showControls) {
 }
 
 bool BmpViewerActivity::renderDecodedImage(const bool showControls) {
+  RenderLock lock(*this);
   const auto pageWidth = renderer.getScreenWidth();
   const auto pageHeight = renderer.getScreenHeight();
   Rect popupRect = GUI.drawPopup(renderer, tr(STR_LOADING_POPUP));
@@ -291,8 +293,11 @@ void BmpViewerActivity::toggleDisplayMode() {
   grayscaleDisplay = !grayscaleDisplay;
   // Switching between 1-bit BW and 4-level grayscale requires a full refresh to clear
   // ghosting from the previous mode — a half refresh leaves visible residue.
-  renderer.clearScreen();
-  renderer.displayBuffer(HalDisplay::FULL_REFRESH);
+  {
+    RenderLock lock(*this);
+    renderer.clearScreen();
+    renderer.displayBuffer(HalDisplay::FULL_REFRESH);
+  }
   if (!renderCurrentImage()) {
     renderError(tr(STR_COULD_NOT_RENDER_IMAGE));
   }
@@ -335,6 +340,7 @@ void BmpViewerActivity::saveDitherSettingsIfNeeded() {
 #endif
 
 void BmpViewerActivity::renderError(const char* message) {
+  RenderLock lock(*this);
   const auto pageHeight = renderer.getScreenHeight();
   renderer.clearScreen();
   renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2, message);
@@ -365,8 +371,11 @@ void BmpViewerActivity::setAsSleepScreen() {
 
   if (!success) {
     LOG_ERR("BMP", "Failed to set %s as sleep screen", filePath.c_str());
-    GUI.drawPopup(renderer, tr(STR_FAILED_TO_SET_SLEEP_SCREEN));
-    renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+    {
+      RenderLock lock(*this);
+      GUI.drawPopup(renderer, tr(STR_FAILED_TO_SET_SLEEP_SCREEN));
+      renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+    }
     return;
   }
 
@@ -374,8 +383,11 @@ void BmpViewerActivity::setAsSleepScreen() {
   SETTINGS.saveToFile();
   LOG_INF("BMP", "Set %s as sleep screen", filePath.c_str());
 
-  GUI.drawPopup(renderer, tr(STR_SLEEP_SCREEN_SET));
-  renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+  {
+    RenderLock lock(*this);
+    GUI.drawPopup(renderer, tr(STR_SLEEP_SCREEN_SET));
+    renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+  }
 }
 
 void BmpViewerActivity::loop() {
diff --git a/src/activities/util/FullScreenMessageActivity.cpp b/src/activities/util/FullScreenMessageActivity.cpp
index 3b7428ab..144cd746 100644
--- a/src/activities/util/FullScreenMessageActivity.cpp
+++ b/src/activities/util/FullScreenMessageActivity.cpp
@@ -6,6 +6,7 @@
 
 void FullScreenMessageActivity::onEnter() {
   Activity::onEnter();
+  RenderLock lock(*this);
 
   const auto height = renderer.getLineHeight(UI_10_FONT_ID);
   const auto top = (renderer.getScreenHeight() - height) / 2;
diff --git a/src/activities/weather/WeatherActivity.cpp b/src/activities/weather/WeatherActivity.cpp
index dc382a83..51e2ec96 100644
--- a/src/activities/weather/WeatherActivity.cpp
+++ b/src/activities/weather/WeatherActivity.cpp
@@ -202,7 +202,10 @@ void WeatherActivity::onEnter() {
   Activity::onEnter();
 
   // Force landscape orientation for weather display
-  renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
+  {
+    RenderLock lock(*this);
+    renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
+  }
 
   state = State::LOADING_CACHE;
   errorMessage.clear();
@@ -217,7 +220,10 @@ void WeatherActivity::onExit() {
   Activity::onExit();
 
   // Weather screen is always landscape; restore app UI to portrait on exit.
-  renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  {
+    RenderLock lock(*this);
+    renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  }
 
   WiFi.mode(WIFI_OFF);
 }
@@ -283,7 +289,10 @@ void WeatherActivity::launchWifiSelection() {
 
 void WeatherActivity::onWifiSelectionComplete(bool connected) {
   // Re-apply landscape after returning from WiFi selection (which uses portrait)
-  renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
+  {
+    RenderLock lock(*this);
+    renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
+  }
   LOG_DBG("WEA", "onWifiSelectionComplete connected=%d wifiStatus=%d", connected ? 1 : 0, (int)WiFi.status());
 
   if (connected) {
@@ -325,10 +334,16 @@ void WeatherActivity::fetchWeather() {
 }
 
 void WeatherActivity::openSettingsActivity() {
-  renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  {
+    RenderLock lock(*this);
+    renderer.setOrientation(GfxRenderer::Orientation::Portrait);
+  }
   startActivityForResult(std::make_unique<WeatherSettingsActivity>(renderer, mappedInput),
                          [this](const ActivityResult&) {
-                           renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
+                           {
+                             RenderLock lock(*this);
+                             renderer.setOrientation(GfxRenderer::Orientation::LandscapeClockwise);
+                           }
                            forceRefresh = true;
                            loadAndDisplay();
                          });