diff --git a/ChangeLog b/ChangeLog
index 9447249f7..4eb39b900 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2013-11-08  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/normal/datetime.c (grub_get_weekday): Use unsigned types.
+
 2013-11-08  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/gfxmenu/gui_circular_progress.c (parse_angle):
diff --git a/grub-core/normal/datetime.c b/grub-core/normal/datetime.c
index 2b0faca90..7e548acdf 100644
--- a/grub-core/normal/datetime.c
+++ b/grub-core/normal/datetime.c
@@ -34,7 +34,7 @@ static const char *const grub_weekday_names[] =
 int
 grub_get_weekday (struct grub_datetime *datetime)
 {
-  int a, y, m;
+  unsigned a, y, m;
 
   a = (14 - datetime->month) / 12;
   y = datetime->year - a;