diff --git a/src/znordic.c b/src/znordic.c
index cf55dc4..924ec3e 100644
--- a/src/znordic.c
+++ b/src/znordic.c
@@ -108,10 +108,9 @@ int16_t znrf_adc_channel_read_val(uint16_t channel) {
  *                                     RTC                                     *
  *******************************************************************************/
 volatile uint32_t g_timestamp    = 0;
-volatile uint32_t g_power_on_rtc = 0;
+volatile uint32_t g_power_on_rtc = 1704038400;  //  2024/01/01/00:00:00
 // static uint8_t    s_timeCount1second = 0;
 
-
 uint32_t znordic_getpower_on_ms() {
   __disable_irq();
   uint32_t ret = g_timestamp * 125;
@@ -152,7 +151,12 @@ void     znordic_rtc_settime(uint16_t year, uint8_t month, uint8_t day, uint8_t
   s_tm.tm_isdst = -1;
 
   uint32_t nowtimestamp = mktime(&s_tm);
-  g_power_on_rtc        = nowtimestamp - znordic_getpower_on_s();
+  uint32_t tosettime    = nowtimestamp - znordic_getpower_on_s();
+
+  if (tosettime > 1704038400) {  //  2024/01/01/00:00:00
+    g_power_on_rtc = tosettime;
+  }
+  return;
 }
 
 void znordic_rtc_gettime(ztm_t* now) {