diff --git a/ChangeLog b/ChangeLog
index 80c774256..28cb5d792 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-14  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/disk/dmraid_nvidia.c (grub_dmraid_nv_detect): Skip
+	disks with unknown size.
+	* grub-core/disk/raid.c (scan_devices): Allow disks with unknown sizes.
+
 2012-01-14  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Remove defines pertaining to arbitrary limits not affecting GRUB
diff --git a/grub-core/disk/dmraid_nvidia.c b/grub-core/disk/dmraid_nvidia.c
index 154193eb0..08600519a 100644
--- a/grub-core/disk/dmraid_nvidia.c
+++ b/grub-core/disk/dmraid_nvidia.c
@@ -100,8 +100,10 @@ grub_dmraid_nv_detect (grub_disk_t disk, struct grub_raid_array *array,
   if (disk->partition)
     return grub_error (GRUB_ERR_OUT_OF_RANGE, "skip partition");
 
-  sector = grub_disk_get_size (disk) - 2;
-
+  sector = grub_disk_get_size (disk);
+  if (sector == GRUB_DISK_SIZE_UNKNOWN)
+    return grub_error (GRUB_ERR_OUT_OF_RANGE, "not raid");
+  sector -= 2;
   if (grub_disk_read (disk, sector, 0, sizeof (sb), &sb))
     return grub_errno;
 
diff --git a/grub-core/disk/raid.c b/grub-core/disk/raid.c
index db1e969b3..490cfa92a 100644
--- a/grub-core/disk/raid.c
+++ b/grub-core/disk/raid.c
@@ -131,8 +131,7 @@ scan_devices (const char *arname)
 	      }
 	}
 
-      if ((disk->total_sectors != GRUB_ULONG_MAX) &&
-	  (! raid->detect (disk, &array, &start_sector)) &&
+      if ((! raid->detect (disk, &array, &start_sector)) &&
 	  (! insert_array (disk, &array, start_sector, raid->name,
 			   raid)))
 	return 0;