diff --git a/cpu/cc430/cc430-rtc.c b/cpu/cc430/cc430-rtc.c
index 8c9519c6d6..189aef0fcd 100644
--- a/cpu/cc430/cc430-rtc.c
+++ b/cpu/cc430/cc430-rtc.c
@@ -197,7 +197,7 @@ interrupt(RTC_VECTOR) __attribute__((naked)) rtc_isr(void)
         }
 
         if (rtc_second_pid) {
-            msg_t m;
+            static msg_t m;
             m.type = RTC_SECOND;
             msg_send_int(&m, rtc_second_pid);
         }