diff --git a/firmware/common/timefuncs.c b/firmware/common/timefuncs.c
index 42babbd8e3..7d385949b5 100644
--- a/firmware/common/timefuncs.c
+++ b/firmware/common/timefuncs.c
@@ -99,7 +99,7 @@ int set_time(const struct tm *tm)
     }
 #else /* No RTC */
     (void)tm;
-    return 0;
+    return -1;
 #endif /* RTC */
 }
 
diff --git a/firmware/target/hosted/rtc.c b/firmware/target/hosted/rtc.c
index 179e7ea909..8c430f3774 100644
--- a/firmware/target/hosted/rtc.c
+++ b/firmware/target/hosted/rtc.c
@@ -36,5 +36,5 @@ int rtc_read_datetime(struct tm *tm)
 int rtc_write_datetime(const struct tm *tm)
 {
     (void)tm;
-    return 0;
+    return -1;
 }