diff --git a/src/helpers/sensors/EnvironmentSensorManager.cpp b/src/helpers/sensors/EnvironmentSensorManager.cpp
index 73842d9eeb..e2e7dbf7ea 100644
--- a/src/helpers/sensors/EnvironmentSensorManager.cpp
+++ b/src/helpers/sensors/EnvironmentSensorManager.cpp
@@ -889,11 +889,11 @@ void EnvironmentSensorManager::stop_gps() {
 void EnvironmentSensorManager::loop() {
 
   #if ENV_INCLUDE_GPS
-  static long next_gps_update = 0;
+  static uint32_t last_gps_update = 0;
   if (gps_active) {
     _location->loop();
   }
-  if (millis() > next_gps_update) {
+  if ((uint32_t)(millis() - last_gps_update) >= (uint32_t)(gps_update_interval_sec * 1000)) {
 
     if(gps_active){
     #ifdef RAK_WISBLOCK_GPS
@@ -914,7 +914,7 @@ void EnvironmentSensorManager::loop() {
     }
     #endif
     }
-    next_gps_update = millis() + (gps_update_interval_sec * 1000);
+    last_gps_update = millis();
   }
   #endif
   #if ENV_INCLUDE_BME680_BSEC
diff --git a/src/helpers/sensors/MicroNMEALocationProvider.h b/src/helpers/sensors/MicroNMEALocationProvider.h
index eec466d3aa..c39b413d84 100644
--- a/src/helpers/sensors/MicroNMEALocationProvider.h
+++ b/src/helpers/sensors/MicroNMEALocationProvider.h
@@ -42,7 +42,7 @@ class MicroNMEALocationProvider : public LocationProvider {
     int8_t _claims = 0;
     int _pin_reset;
     int _pin_en;
-    long next_check = 0;
+    uint32_t last_check = 0;
     long time_valid = 0;
     unsigned long _last_time_sync = 0;
     static const unsigned long TIME_SYNC_INTERVAL = 1800000; // Re-sync every 30 minutes
@@ -143,10 +143,11 @@ public :
 
         if (!isValid()) time_valid = 0;
 
-        if (millis() > next_check) {
-            next_check = millis() + 1000;
+        if ((uint32_t)(millis() - last_check) >= 1000) {
+            last_check = millis();
             // Re-enable time sync periodically when GPS has valid fix
-            if (!_time_sync_needed && _clock != NULL && (millis() - _last_time_sync) > TIME_SYNC_INTERVAL) {
+            if (!_time_sync_needed && _clock != NULL &&
+                (uint32_t)(millis() - _last_time_sync) > TIME_SYNC_INTERVAL) {
                 _time_sync_needed = true;
             }
             if (_time_sync_needed && time_valid > 2) {
diff --git a/variants/heltec_mesh_solar/target.cpp b/variants/heltec_mesh_solar/target.cpp
index d140864cd1..c4000132fe 100644
--- a/variants/heltec_mesh_solar/target.cpp
+++ b/variants/heltec_mesh_solar/target.cpp
@@ -65,18 +65,18 @@ bool SolarSensorManager::querySensors(uint8_t requester_permissions, CayenneLPP&
 }
 
 void SolarSensorManager::loop() {
-  static long next_gps_update = 0;
+  static uint32_t last_gps_update = 0;
 
   _location->loop();
 
-  if (millis() > next_gps_update) {
+  if ((uint32_t)(millis() - last_gps_update) >= 1000) {
     if (_location->isValid()) {
       node_lat = ((double)_location->getLatitude())/1000000.;
       node_lon = ((double)_location->getLongitude())/1000000.;
       node_altitude = ((double)_location->getAltitude()) / 1000.0;
       MESH_DEBUG_PRINTLN("lat %f lon %f", node_lat, node_lon);
     }
-    next_gps_update = millis() + 1000;
+    last_gps_update = millis();
   }
 }
 
diff --git a/variants/heltec_tracker/target.cpp b/variants/heltec_tracker/target.cpp
index f32c41ff47..62a28ece7f 100644
--- a/variants/heltec_tracker/target.cpp
+++ b/variants/heltec_tracker/target.cpp
@@ -71,18 +71,18 @@ bool HWTSensorManager::querySensors(uint8_t requester_permissions, CayenneLPP& t
 }
 
 void HWTSensorManager::loop() {
-  static long next_gps_update = 0;
+  static uint32_t last_gps_update = 0;
 
   _location->loop();
 
-  if (millis() > next_gps_update) {
+  if ((uint32_t)(millis() - last_gps_update) >= 1000) {
     if (gps_active && _location->isValid()) {
       node_lat = ((double)_location->getLatitude())/1000000.;
       node_lon = ((double)_location->getLongitude())/1000000.;
       node_altitude = ((double)_location->getAltitude()) / 1000.0;
       MESH_DEBUG_PRINTLN("lat %f lon %f", node_lat, node_lon);
     }
-    next_gps_update = millis() + 1000;
+    last_gps_update = millis();
   }
 }
 
diff --git a/variants/meshadventurer/target.cpp b/variants/meshadventurer/target.cpp
index 8795a4cbe7..a2d1a0e5fb 100644
--- a/variants/meshadventurer/target.cpp
+++ b/variants/meshadventurer/target.cpp
@@ -65,16 +65,16 @@ bool MASensorManager::querySensors(uint8_t requester_permissions, CayenneLPP& te
 }
 
 void MASensorManager::loop() {
-  static long next_gps_update = 0;
+  static uint32_t last_gps_update = 0;
   _location->loop();
-  if(millis() > next_gps_update && gps_active) {
+  if (gps_active && (uint32_t)(millis() - last_gps_update) >= 1000) {
     if(_location->isValid()) {
       node_lat = ((double)_location->getLatitude()) / 1000000.;
       node_lon = ((double)_location->getLongitude()) / 1000000.;
       node_altitude = ((double)_location->getAltitude()) / 1000.0;
       MESH_DEBUG_PRINTLN("lat %f lon %f", node_lat, node_lon);
     }
-    next_gps_update = millis() + 1000;
+    last_gps_update = millis();
   }
 }
 
diff --git a/variants/nano_g2_ultra/target.cpp b/variants/nano_g2_ultra/target.cpp
index 69a2772ccb..f72a7b61d2 100644
--- a/variants/nano_g2_ultra/target.cpp
+++ b/variants/nano_g2_ultra/target.cpp
@@ -73,7 +73,7 @@ bool NanoG2UltraSensorManager::querySensors(uint8_t requester_permissions, Cayen
 }
 
 void NanoG2UltraSensorManager::loop() {
-  static long next_gps_update = 0;
+  static uint32_t last_gps_update = 0;
 
   if (!gps_active) {
     return; // GPS is not active, skip further processing
@@ -81,7 +81,7 @@ void NanoG2UltraSensorManager::loop() {
 
   _location->loop();
 
-  if (millis() > next_gps_update) {
+  if ((uint32_t)(millis() - last_gps_update) >= 1000) {
     if (_location->isValid()) {
       node_lat = ((double)_location->getLatitude()) / 1000000.;
       node_lon = ((double)_location->getLongitude()) / 1000000.;
@@ -91,7 +91,7 @@ void NanoG2UltraSensorManager::loop() {
       MESH_DEBUG_PRINTLN("INVALID location, waiting for fix");
     }
     MESH_DEBUG_PRINTLN("GPS satellites: %d", _location->satellitesCount());
-    next_gps_update = millis() + 1000;
+    last_gps_update = millis();
   }
 }
 
diff --git a/variants/t1000-e/t1000e_sensors.cpp b/variants/t1000-e/t1000e_sensors.cpp
index 85298d3a82..8717ad54ca 100644
--- a/variants/t1000-e/t1000e_sensors.cpp
+++ b/variants/t1000-e/t1000e_sensors.cpp
@@ -32,11 +32,12 @@ static int8_t ntc_temp2[136] = {
 };
 
 static float get_heater_temperature(unsigned int vcc_volt, unsigned int ntc_volt) {
+  if (ntc_volt == 0) {
+    return 0.0f;  // avoid division by zero on open circuit / sensor fault
+  }
   int i = 0;
-  float Vout = 0, Rt = 0, temp = 0;
-  Vout = ntc_volt;
-
-  Rt = (HEATER_NTC_RP * vcc_volt) / Vout - HEATER_NTC_RP;
+  float Rt = 0, temp = 0;
+  Rt = (HEATER_NTC_RP * (float)vcc_volt) / ntc_volt - HEATER_NTC_RP;
 
   for (i = 0; i < 136; i++) {
     if (Rt >= ntc_res2[i]) {
@@ -44,7 +45,17 @@ static float get_heater_temperature(unsigned int vcc_volt, unsigned int ntc_volt
     }
   }
 
-  temp = ntc_temp2[i - 1] + 1 * (ntc_res2[i - 1] - Rt) / (float)(ntc_res2[i - 1] - ntc_res2[i]);
+  if (i <= 0) {
+    return (float)ntc_temp2[0];
+  }
+  if (i >= 136) {
+    return (float)ntc_temp2[135];
+  }
+  int denom = ntc_res2[i - 1] - ntc_res2[i];
+  if (denom == 0) {
+    return (float)ntc_temp2[i - 1];
+  }
+  temp = ntc_temp2[i - 1] + 1 * (ntc_res2[i - 1] - Rt) / (float)denom;
 
   temp = (temp * 100 + 5) / 100;
   return temp;
diff --git a/variants/t1000-e/target.cpp b/variants/t1000-e/target.cpp
index 4253282708..429c9e9d8a 100644
--- a/variants/t1000-e/target.cpp
+++ b/variants/t1000-e/target.cpp
@@ -147,18 +147,18 @@ bool T1000SensorManager::querySensors(uint8_t requester_permissions, CayenneLPP&
 }
 
 void T1000SensorManager::loop() {
-  static long next_gps_update = 0;
+  static uint32_t last_gps_update = 0;
+  constexpr uint32_t GPS_UPDATE_INTERVAL_MS = 1000;
 
   _nmea->loop();
 
-  if (millis() > next_gps_update) {
+  if ((uint32_t)(millis() - last_gps_update) >= GPS_UPDATE_INTERVAL_MS) {
     if (gps_active && _nmea->isValid()) {
       node_lat = ((double)_nmea->getLatitude())/1000000.;
       node_lon = ((double)_nmea->getLongitude())/1000000.;
       node_altitude = ((double)_nmea->getAltitude()) / 1000.0;
-      //Serial.printf("lat %f lon %f\r\n", _lat, _lon);
     }
-    next_gps_update = millis() + 1000;
+    last_gps_update = millis();
   }
 }
 
diff --git a/variants/thinknode_m1/target.cpp b/variants/thinknode_m1/target.cpp
index 69306fc0e1..c19f9ca846 100644
--- a/variants/thinknode_m1/target.cpp
+++ b/variants/thinknode_m1/target.cpp
@@ -69,17 +69,17 @@ bool ThinkNodeM1SensorManager::querySensors(uint8_t requester_permissions, Cayen
 }
 
 void ThinkNodeM1SensorManager::loop() {
-  static long next_gps_update = 0;
-  static long last_switch_check = 0;
+  static uint32_t last_gps_update = 0;
+  static uint32_t last_switch_check = 0;
 
   // Check GPS switch state every second
-  if (millis() - last_switch_check > 1000) {
+  if ((uint32_t)(millis() - last_switch_check) >= 1000) {
     bool current_switch_state = digitalRead(PIN_GPS_SWITCH);
-    
+
     // Detect switch state change
     if (current_switch_state != last_gps_switch_state) {
       last_gps_switch_state = current_switch_state;
-      
+
       if (current_switch_state == HIGH) {  // Switch is ON
         MESH_DEBUG_PRINTLN("GPS switch ON");
         start_gps();
@@ -88,7 +88,7 @@ void ThinkNodeM1SensorManager::loop() {
         stop_gps();
       }
     }
-    
+
     last_switch_check = millis();
   }
 
@@ -98,14 +98,14 @@ void ThinkNodeM1SensorManager::loop() {
 
   _location->loop();
 
-  if (millis() > next_gps_update) {
+  if ((uint32_t)(millis() - last_gps_update) >= 1000) {
     if (_location->isValid()) {
       node_lat = ((double)_location->getLatitude())/1000000.;
       node_lon = ((double)_location->getLongitude())/1000000.;
       node_altitude = ((double)_location->getAltitude()) / 1000.0;
       MESH_DEBUG_PRINTLN("lat %f lon %f", node_lat, node_lon);
     }
-    next_gps_update = millis() + 1000;
+    last_gps_update = millis();
   }
 }