diff --git a/src/main.cpp b/src/main.cpp
index f1f6188a..ba5d4608 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -200,6 +200,7 @@ void waitForPowerRelease() {
 
 // Enter deep sleep mode
 void enterDeepSleep() {
+  HalPowerManager::Lock powerLock;  // Ensure we are at normal CPU frequency for sleep preparation
   APP_STATE.lastSleepFromReader = currentActivity && currentActivity->isReaderActivity();
   APP_STATE.saveToFile();
   exitActivity();