diff --git a/configure.ac b/configure.ac
index ae7cd238..58b78ac5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -177,7 +177,7 @@ AC_ARG_WITH(plugin-path,
 	[plugin_path=$withval], [plugin_path=yes])
 
 AC_ARG_WITH(rtc-date,
-	AS_HELP_STRING([--with-rtc-date=DATE], [If RTC date/time is too old, restore to DATE, format "YYYY-MM-DD HH:MM", default "2000-01-01 00:00"]),
+	AS_HELP_STRING([--with-rtc-date=DATE], [If RTC date/time is too old, restore to DATE, format "YYYY-MM-DD HH:MM:SS", default "2000-01-01 00:00:00"]),
 	[rtc_date=$withval], [rtc_date=no])
 
 AC_ARG_WITH(rtc-file,
@@ -282,7 +282,7 @@ AS_IF([test "x$with_random_seed" != "xno"], [
 	AC_DEFINE_UNQUOTED(RANDOMSEED, "$random_path", [Improve random at boot by seeding it with sth from before.])])
 
 AS_IF([test "x$rtc_date" != "xno"], [
-	AC_DEFINE(RTC_TIMESTAMP_CUSTOM, "$rtc_date", [Custom RTC restore date, default: 2000-01-01 00:00])], [
+	AC_DEFINE_UNQUOTED(RTC_TIMESTAMP_CUSTOM, "$rtc_date", [Custom RTC restore date, default: 2000-01-01 00:00])], [
 	rtc_date=""])
 
 AS_IF([test "x$rtc_file" != "xno"], [
diff --git a/plugins/rtc.c b/plugins/rtc.c
index 9b4eeae5..a733f754 100644
--- a/plugins/rtc.c
+++ b/plugins/rtc.c
@@ -321,10 +321,12 @@ PLUGIN_INIT(plugin_init)
 {
 	struct tm tm = { 0 };
 
-	if (!strptime(rtc_timestamp, "%Y-%m-%d %H:%M", &tm))
-		rtc_date_fallback = mktime(&tm);
-	else
+	if (!strptime(rtc_timestamp, RTC_FMT, &tm)) {
+		logit(LOG_ERR, "Invalid restore date '%s', reverting to '%s'",
+		      rtc_timestamp, RTC_TIMESTAMP_BEGIN_2000);
 		rtc_timestamp = RTC_TIMESTAMP_BEGIN_2000;
+	} else
+		rtc_date_fallback = mktime(&tm);
 
 	uev_timer_init(ctx, &rtc_timer, update, NULL, RTC_PERIOD, RTC_PERIOD);