diff --git a/ampel-firmware/ampel-firmware.ino b/ampel-firmware/ampel-firmware.ino
index 2713e2dc76413d27a673f9ac1e63b29b3c3cdbe3..9e2ee0c5ded00bb8a85163b5ecc577cac4d323f5 100644
--- a/ampel-firmware/ampel-firmware.ino
+++ b/ampel-firmware/ampel-firmware.ino
@@ -76,7 +76,6 @@ void setup() {
   Serial.println(BOARD);
 
 #ifdef AMPEL_WIFI
-  // Try to connect to Wi-Fi
   WiFiConnect(SENSOR_ID);
 
   Serial.print(F("WiFi STATUS: "));
@@ -126,7 +125,7 @@ void loop() {
   }
 #endif
   //NOTE: Loop should never take more than 1000ms. Split in smaller methods and logic if needed.
-  //TODO: Restart every day or week, in order to not let t0 overflow?
+  //NOTE: Only use millis() for duration comparison, not timestamps comparison. Otherwise, problems happen when millis roll over.
   uint32_t t0 = millis();
 
   keepServicesAlive();
diff --git a/ampel-firmware/util.h b/ampel-firmware/util.h
index 0ffe5eb4d35d2243512035c07e09c1d44464fea8..2997933480b06db67b18a09bafa2d156d8b7e7b5 100644
--- a/ampel-firmware/util.h
+++ b/ampel-firmware/util.h
@@ -36,6 +36,7 @@ namespace util {
   }
 }
 
+//NOTE: Only use seconds() for duration comparison, not timestamps comparison. Otherwise, problems happen when millis roll over.
 #define seconds() (millis() / 1000UL)
 extern uint32_t max_loop_duration;
 const extern String SENSOR_ID;