diff --git a/src/main.cpp b/src/main.cpp
index 56897d0..3fc4d28 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -105,38 +105,9 @@ BleFingerprint *getFingerprint(BLEAdvertisedDevice *advertisedDevice)
     return created;
 }
 
-/**
- * CalculateUptimeSeconds()
- *
- * Handle millis() rollover and calculate the total uptime in seconds.
- * This function must be called at least once for every 50 days to be
- * able to see the rollover.
- */
-unsigned long CalculateUptimeSeconds(void)
+unsigned long getUptimeSeconds(void)
 {
-    static unsigned int _rolloverCount = 0; // Number of 0xFFFFFFFF rollover we had in millis()
-    static unsigned long _lastMillis = 0;   // Value of the last millis()
-
-    // Get the current milliseconds uptime from the system.
-    // Note: This only works as long as no one else did hook up with timer0
-    //       because the arduino system uses timer0 to manage delay() and millis().
-    unsigned long currentMilliSeconds = millis();
-
-    // If we had a rollover we count that.
-    if (currentMilliSeconds < _lastMillis)
-    {
-        _rolloverCount++;
-    }
-
-    // Now store the current number of milliseconds for the next round.
-    _lastMillis = currentMilliSeconds;
-
-    // Based on the current milliseconds and the number of rollovers
-    // we had in total we calculate here the uptime in seconds since
-    // poweron or reset.
-    // Caution: Because we shorten millis to seconds we may miss one
-    // second for every rollover (1 second every 50 days).
-    return (0xFFFFFFFF / 1000) * _rolloverCount + (_lastMillis / 1000);
+    return esp_timer_get_time() / 1e6;
 }
 
 bool sendTelemetry(int totalSeen = -1, int totalReported = -1, int totalAdverts = -1)
@@ -147,7 +118,7 @@ bool sendTelemetry(int totalSeen = -1, int totalReported = -1, int totalAdverts
     tele["hostname"] = WiFi.getHostname();
     tele["scan_dur"] = BLE_SCAN_DURATION;
     tele["max_dist"] = MAX_DISTANCE;
-    tele["uptime"] = CalculateUptimeSeconds();
+    tele["uptime"] = getUptimeSeconds();
     tele["firm"] = String(FIRMWARE);
 
 #ifdef VERSION
@@ -199,7 +170,7 @@ void connectToWifi()
         return 500;                                           // Delay next function call by 500ms
     };
     WiFiSettings.onPortalWaitLoop = []() {
-        if (CalculateUptimeSeconds() > 600)
+        if (getUptimeSeconds() > 600)
             ESP.restart();
     };
 
@@ -447,7 +418,7 @@ void firmwareUpdate()
 {
 #ifdef VERSION
     static long lastFirmwareCheck = 0;
-    long uptime = CalculateUptimeSeconds();
+    long uptime = getUptimeSeconds();
     if (uptime - lastFirmwareCheck < CHECK_FOR_UPDATES_INTERVAL)
         return;