diff --git a/drivers/rtc/m41t60.c b/drivers/rtc/m41t60.c
index 8a32ea0..ef135ca 100644
--- a/drivers/rtc/m41t60.c
+++ b/drivers/rtc/m41t60.c
@@ -241,7 +241,7 @@
 
 		if (l <= 0x3F) {
 			if ((data[RTC_CTRL] & 0x3F) != l) {
-				printf("Setting RTC calibration to 0x%02X\n",
+				printf("Setting RTC calibration to 0x%02lX\n",
 				       l);
 				data[RTC_CTRL] &= 0xC0;
 				data[RTC_CTRL] |= (uchar) l;