diff --git a/post/drivers/rtc.c b/post/drivers/rtc.c
index 8d7a788..c2e7391 100644
--- a/post/drivers/rtc.c
+++ b/post/drivers/rtc.c
@@ -59,8 +59,7 @@
 
 static void rtc_post_restore (struct rtc_time *tm, unsigned int sec)
 {
-	time_t t = mktime (tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour,
-					   tm->tm_min, tm->tm_sec) + sec;
+	time_t t = rtc_mktime(tm) + sec;
 	struct rtc_time ntm;
 
 	rtc_to_tm(t, &ntm);
@@ -116,9 +115,16 @@
 	rtc_get (&svtm);
 
 	for (i = 0; i < 12; i++) {
-		time_t t = mktime (ynl, i + 1, daysnl[i], 23, 59, 59);
+		time_t t;
 		struct rtc_time tm;
 
+		tm.tm_year = ynl;
+		tm.tm_mon = i + 1;
+		tm.tm_mday = daysnl[i];
+		tm.tm_hour = 23;
+		tm.tm_min = 59;
+		tm.tm_sec = 59;
+		t = rtc_mktime(&tm);
 		rtc_to_tm(t, &tm);
 		rtc_set (&tm);
 
@@ -140,9 +146,17 @@
 	}
 
 	for (i = 0; i < 12; i++) {
-		time_t t = mktime (yl, i + 1, daysl[i], 23, 59, 59);
+		time_t t;
 		struct rtc_time tm;
 
+		tm.tm_year = yl;
+		tm.tm_mon = i + 1;
+		tm.tm_mday = daysl[i];
+		tm.tm_hour = 23;
+		tm.tm_min = 59;
+		tm.tm_sec = 59;
+		t = rtc_mktime(&tm);
+
 		rtc_to_tm(t, &tm);
 		rtc_set (&tm);