diff --git a/include/lorawan.h b/include/lorawan.h
index 394284be..0c870bb9 100644
--- a/include/lorawan.h
+++ b/include/lorawan.h
@@ -1,3 +1,5 @@
+#if (HAS_LORA)
+
 #ifndef _LORAWAN_H
 #define _LORAWAN_H
 
@@ -48,4 +50,6 @@ const char *getCrName(rps_t rps);
 void showLoraKeys(void);
 #endif // VERBOSE
 
-#endif
\ No newline at end of file
+#endif
+
+#endif // HAS_LORA
\ No newline at end of file
diff --git a/include/timekeeper.h b/include/timekeeper.h
index bb97a043..ee20913e 100644
--- a/include/timekeeper.h
+++ b/include/timekeeper.h
@@ -10,6 +10,8 @@
 #include "dcf77.h"
 #include "esp_sntp.h"
 
+#define HAS_LORA_TIME ((HAS_LORA) && ((TIME_SYNC_LORASERVER) || (TIME_SYNC_LORAWAN)))
+
 #define SECS_YR_2000 (946684800UL)    // the time at the start of y2k
 #define GPS_UTC_DIFF 315964800UL      // seconds diff between gps and utc epoch
 #define LEAP_SECS_SINCE_GPSEPOCH 18UL // state of 2021
@@ -32,7 +34,7 @@ void setTimeSyncIRQ(void);
 uint8_t timepulse_init(void);
 bool timeIsValid(time_t const t);
 void calibrateTime(void);
-void IRAM_ATTR setMyTime(uint32_t t_sec, uint16_t t_msec,
+bool IRAM_ATTR setMyTime(uint32_t t_sec, uint16_t t_msec,
                          timesource_t mytimesource);
 time_t compileTime(void);
 time_t mkgmtime(const struct tm *ptm);
diff --git a/src/timekeeper.cpp b/src/timekeeper.cpp
index 6a4d2904..f2765bf7 100644
--- a/src/timekeeper.cpp
+++ b/src/timekeeper.cpp
@@ -1,13 +1,5 @@
 #include "timekeeper.h"
 
-#if !(HAS_LORA)
-#if (TIME_SYNC_LORASERVER)
-#error TIME_SYNC_LORASERVER defined, but device has no LORA configured
-#elif (TIME_SYNC_LORAWAN)
-#error TIME_SYNC_LORAWAN defined, but device has no LORA configured
-#endif
-#endif
-
 #if (defined HAS_DCF77 && defined HAS_IF482)
 #error You must define at most one of IF482 or DCF77!
 #endif
@@ -44,48 +36,38 @@ void calibrateTime(void) {
   time_t t = 0;
   uint16_t t_msec = 0;
 
-  // kick off asychronous lora timesync if we have
-#if (HAS_LORA) && ((TIME_SYNC_LORASERVER) || (TIME_SYNC_LORAWAN))
+  // kick off asynchronous lora timesync if we have
+#if (HAS_LORA_TIME)
   timesync_request();
-#endif
-
-  // if no LORA timesource is available, or if we lost time, then fallback to
-  // local time source RTS or GPS
-  if (((!TIME_SYNC_LORASERVER) && (!TIME_SYNC_LORAWAN)) ||
-      (timeSource == _unsynced)) {
-
-// has RTC -> fallback to RTC time
-#ifdef HAS_RTC
-    t = get_rtctime(&t_msec);
-    // set time from RTC - method will check if time is valid
-    setMyTime((uint32_t)t, t_msec, _rtc);
-#endif
-
-// no RTC -> fallback to GPS time
-#if (HAS_GPS)
-    t = get_gpstime(&t_msec);
-    // set time from GPS - method will check if time is valid
-    setMyTime((uint32_t)t, t_msec, _gps);
-#endif
-
-  } // fallback
-
-  else
-
-    // no fallback time source available -> we can't set time
+  if (timeSource == _lora) // did have lora time before?
     return;
+#endif
+
+// get GPS time, if we have
+#if (HAS_GPS)
+  t = get_gpstime(&t_msec);
+  if (setMyTime((uint32_t)t, t_msec, _gps))
+    return;
+#endif
+
+// fallback to RTC time, if we have
+#ifdef HAS_RTC
+  t = get_rtctime(&t_msec);
+  if (setMyTime((uint32_t)t, t_msec, _rtc))
+    return;
+#endif
 
 } // calibrateTime()
 
 // set system time (UTC), calibrate RTC and RTC_INT pps
-void IRAM_ATTR setMyTime(uint32_t t_sec, uint16_t t_msec,
+bool IRAM_ATTR setMyTime(uint32_t t_sec, uint16_t t_msec,
                          timesource_t mytimesource) {
 
   struct timeval tv = {0};
 
   // called with invalid timesource?
   if (mytimesource == _unsynced)
-    return;
+    return false;
 
   // increment t_sec if t_msec > 1000
   time_t time_to_set = (time_t)(t_sec + t_msec / 1000);
@@ -126,13 +108,17 @@ void IRAM_ATTR setMyTime(uint32_t t_sec, uint16_t t_msec,
     timesyncer.attach(TIME_SYNC_INTERVAL * 60, setTimeSyncIRQ);
     ESP_LOGD(TAG, "[%0.3f] Timesync finished, time was set | timesource=%d",
              _seconds(), mytimesource);
+    return true;
+
   } else {
+
     timesyncer.attach(TIME_SYNC_INTERVAL_RETRY * 60, setTimeSyncIRQ);
     ESP_LOGV(TAG,
              "[%0.3f] Failed to synchronise time from source %c | unix sec "
              "obtained from source: %d | unix sec at program compilation: %d",
              _seconds(), timeSetSymbols[mytimesource], time_to_set,
              compileTime());
+    return false;
   }
 }
 
@@ -172,7 +158,7 @@ uint8_t timepulse_init() {
   // use ESP32 hardware timer as time base for calendar time
   ppsIRQ = timerBegin(1, 8000, true);   // set 80 MHz prescaler to 1/10000 sec
   timerAlarmWrite(ppsIRQ, 10000, true); // 1000ms
-  timerAttachInterrupt(ppsIRQ, &CLOCKIRQ, true);
+  timerAttachInterrupt(ppsIRQ, &CLOCKIRQ, false);
   timerAlarmEnable(ppsIRQ);
   ESP_LOGI(TAG, "Timepulse: internal (ESP32 hardware timer)");
   return 1; // success
diff --git a/src/timesync.cpp b/src/timesync.cpp
index 9b2c5f99..80355eb8 100644
--- a/src/timesync.cpp
+++ b/src/timesync.cpp
@@ -13,6 +13,8 @@ accept this.
 
 */
 
+#if (HAS_LORA)
+
 #if (TIME_SYNC_LORASERVER) && (TIME_SYNC_LORAWAN)
 #error Duplicate timesync method selected. You must select either LORASERVER or LORAWAN timesync.
 #endif
@@ -173,7 +175,7 @@ void timesync_store(uint32_t timestamp, timesync_t timestamp_type) {
 // callback function to receive time answer from network or answer
 void IRAM_ATTR timesync_serverAnswer(void *pUserData, int flag) {
 
-#if (TIME_SYNC_LORASERVER) || (TIME_SYNC_LORAWAN)
+#if (HAS_LORA_TIME)
 
   // if no timesync handshake is pending then exit
   if (!timeSyncPending)
@@ -277,5 +279,7 @@ Exit:
   xTaskNotify(timeSyncProcTask, (rc ? rcv_seqNo : TIME_SYNC_END_FLAG),
               eSetBits);
 
-#endif // (TIME_SYNC_LORASERVER) || (TIME_SYNC_LORAWAN)
-}
\ No newline at end of file
+#endif // (HAS_LORA_TIME)
+}
+
+#endif // HAS_LORA
\ No newline at end of file