diff --git a/ChangeLog b/ChangeLog
index cf5cae534..d02901863 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-09-23  Grégoire Sutre  <gregoire.sutre@gmail.com>
+
+	* grub-core/commands/acpihalt.c (get_sleep_type): Initialize prev.
+
 2010-09-23  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Support xz compression on yeeloong.
diff --git a/grub-core/commands/acpihalt.c b/grub-core/commands/acpihalt.c
index 0cd32f389..a39635677 100644
--- a/grub-core/commands/acpihalt.c
+++ b/grub-core/commands/acpihalt.c
@@ -136,7 +136,7 @@ skip_ext_op (const grub_uint8_t *ptr, const grub_uint8_t *end)
 static int
 get_sleep_type (grub_uint8_t *table, grub_uint8_t *end)
 {
-  grub_uint8_t *ptr, *prev;
+  grub_uint8_t *ptr, *prev = table;
   int sleep_type = -1;
   
   ptr = table + sizeof (struct grub_acpi_table_header);