diff --git a/src/main.cpp b/src/main.cpp
index d5b4927..e82dfbc 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -111,6 +111,15 @@ struct __attribute__((packed)) SENSOR_DATA {
   float rssi;
 } sd;
 
+static uint32_t cal = system_rtc_clock_cali_proc(); // WARNING: UPDATING THIS WILL MAKE THE rtcMillis() RETURN A LOWER VALUE THEN BEFORE, EVEN IF TIME PASSED, BREAKING INTERVAL CHECKS!
+unsigned long rtcMillis() {
+  uint64_t rtc_t = system_get_rtc_time();
+//  uint32_t timemicrosec = rtc_t*((uint64) ((cal * 1000) >> 12));
+//  Serial.printf("cal: %d.%d \r\n", ((cal*1000)>>12)/1000, ((cal*1000)>>12)%1000 );
+//  Serial.printf("cal: %u\n", cal);
+  return ((uint64_t)(rtc_t*(uint64_t)cal) >> 12)/1000;
+}
+
 /*
 void sendESPNOW() {
 //  unsigned long espnowmillis = millis();
@@ -170,9 +179,9 @@ void ICACHE_FLASH_ATTR sendValues() {
 
 //  sds.sleep();
 
-  if (millis() - geiger_previousMillis > 60000) {
-    sd.cpm = geiger_counts * 60000 / (millis() - geiger_previousMillis);
-    geiger_previousMillis = millis();
+  if (rtcMillis() - geiger_previousMillis > 60000) {
+    sd.cpm = geiger_counts * 60000 / (rtcMillis() - geiger_previousMillis);
+    geiger_previousMillis = rtcMillis();
     geiger_counts = 0;
     geigeraverage.addValue(sd.cpm);
   }
@@ -255,7 +264,7 @@ void ICACHE_FLASH_ATTR sendValues() {
   if ( ip != INADDR_NONE && dns != INADDR_NONE && gateway != INADDR_NONE && subnet != INADDR_NONE
        && ((ip[0] == 192 && ip[1] == 168) || (ip[0] == 172 && ip[1] == 16))
        && strlen(ssid) > 0 && strlen(password) > 0
-       && (millis() - last_dhcp < dhcp_interval)
+       && (rtcMillis() - last_dhcp < dhcp_interval)
      ) {
 
     DEBUG_MSG("static ip\n");
@@ -303,7 +312,7 @@ void ICACHE_FLASH_ATTR sendValues() {
     subnet = WiFi.subnetMask();
     strncpy(ssid, WiFi.SSID().c_str(), 64);
     strncpy(password, WiFi.psk().c_str(), 64);
-    last_dhcp = millis();
+    last_dhcp = rtcMillis();
   }
 
   sd.rssi = WiFi.RSSI();
@@ -367,7 +376,7 @@ void ICACHE_FLASH_ATTR sendValues() {
   }
   loop_count++;
 
-  last_wifi_activity = millis();
+  last_wifi_activity = rtcMillis();
   WiFi.disconnect();
   WiFi.mode(WIFI_OFF);
   WiFi.forceSleepBegin();
@@ -408,7 +417,7 @@ void setup() {
 }
 
 void loop() {
-  //DEBUG_MSG("%d\n", millis() - last_wifi_activity);
+  //DEBUG_MSG("%d\n", rtcMillis() - last_wifi_activity);
   sendValues();
   delay(postingInterval);
 }