diff --git a/drivers/rtc/mc146818.c b/drivers/rtc/mc146818.c
index ee29c71..4df443d 100644
--- a/drivers/rtc/mc146818.c
+++ b/drivers/rtc/mc146818.c
@@ -145,7 +145,8 @@
 
 	mc146818_write8(RTC_YEAR, bin2bcd(tmp->tm_year % 100));
 	mc146818_write8(RTC_MONTH, bin2bcd(tmp->tm_mon));
-	mc146818_write8(RTC_DAY_OF_WEEK, bin2bcd(tmp->tm_wday));
+	/* Sunday = 1, Saturday = 7 */
+	mc146818_write8(RTC_DAY_OF_WEEK, bin2bcd(tmp->tm_wday + 1));
 	mc146818_write8(RTC_DATE_OF_MONTH, bin2bcd(tmp->tm_mday));
 	mc146818_write8(RTC_HOURS, bin2bcd(tmp->tm_hour));
 	mc146818_write8(RTC_MINUTES, bin2bcd(tmp->tm_min));