diff --git a/arch/sim/src/sim/up_rtc.c b/arch/sim/src/sim/up_rtc.c
index b020bb7266..36c57742f9 100644
--- a/arch/sim/src/sim/up_rtc.c
+++ b/arch/sim/src/sim/up_rtc.c
@@ -128,6 +128,6 @@ int up_rtc_initialize(void)
 #ifdef CONFIG_RTC_RPMSG_SERVER
   rtc = rpmsg_rtc_server_initialize(rtc);
 #endif
-  up_rtc_set_lowerhalf(rtc);
+  up_rtc_set_lowerhalf(rtc, true);
   return rtc_initialize(0, rtc);
 }
diff --git a/boards/sim/sim/sim/src/sim_bringup.c b/boards/sim/sim/sim/src/sim_bringup.c
index d040673729..b497051b3b 100644
--- a/boards/sim/sim/sim/src/sim_bringup.c
+++ b/boards/sim/sim/sim/src/sim_bringup.c
@@ -450,7 +450,7 @@ int sim_bringup(void)
 
 #if defined(CONFIG_RTC_RPMSG) && !defined(CONFIG_RTC_RPMSG_SERVER)
   rtc = rpmsg_rtc_initialize();
-  up_rtc_set_lowerhalf(rtc);
+  up_rtc_set_lowerhalf(rtc, true);
   rtc_initialize(0, rtc);
 #endif
 
diff --git a/drivers/timers/arch_rtc.c b/drivers/timers/arch_rtc.c
index 6e1b90f3a1..c6c3cc10ed 100644
--- a/drivers/timers/arch_rtc.c
+++ b/drivers/timers/arch_rtc.c
@@ -50,13 +50,16 @@ volatile bool g_rtc_enabled = false;
  * Public Functions
  ****************************************************************************/
 
-void up_rtc_set_lowerhalf(FAR struct rtc_lowerhalf_s *lower)
+void up_rtc_set_lowerhalf(FAR struct rtc_lowerhalf_s *lower, bool sync)
 {
   g_rtc_lower   = lower;
   g_rtc_enabled = true;
 
 #ifdef CONFIG_RTC_EXTERNAL
-  clock_synchronize();
+  if (sync)
+    {
+      clock_synchronize();
+    }
 #endif
 }
 
diff --git a/include/nuttx/timers/arch_rtc.h b/include/nuttx/timers/arch_rtc.h
index 2a2a803480..e4092bda75 100644
--- a/include/nuttx/timers/arch_rtc.h
+++ b/include/nuttx/timers/arch_rtc.h
@@ -42,11 +42,11 @@ extern "C"
 
 #ifdef CONFIG_RTC_ARCH
 
-void up_rtc_set_lowerhalf(FAR struct rtc_lowerhalf_s *lower);
+void up_rtc_set_lowerhalf(FAR struct rtc_lowerhalf_s *lower, bool sync);
 
 #else
 
-#  define up_rtc_set_lowerhalf(lower)
+#  define up_rtc_set_lowerhalf(lower, sync)
 
 #endif /* CONFIG_RTC_ARCH */