diff --git a/ChangeLog b/ChangeLog
index ea8804bd1..306358faa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-10-23  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/fs/fat.c (grub_fat_label) [MODE_EXFAT]: Set *label to 0
+	if no label is found.
+	(grub_fat_iterate_dir): Fix file size type.
+	(grub_fat_iterate_dir): Likewise.
+
 2011-10-23  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/lib/reed_solomon.c (gf_invert): Declare as const and
diff --git a/grub-core/fs/fat.c b/grub-core/fs/fat.c
index ae705bcfb..36a43fca0 100644
--- a/grub-core/fs/fat.c
+++ b/grub-core/fs/fat.c
@@ -485,7 +485,7 @@ grub_fat_read_data (grub_disk_t disk, struct grub_fat_data *data,
 			  + data->logical_sector_bits
 			  + GRUB_DISK_SECTOR_BITS);
   logical_cluster = offset >> logical_cluster_bits;
-  offset &= (1 << logical_cluster_bits) - 1;
+  offset &= (1ULL << logical_cluster_bits) - 1;
 
   if (logical_cluster < data->cur_cluster_num)
     {
@@ -631,9 +631,9 @@ grub_fat_iterate_dir (grub_disk_t disk, struct grub_fat_data *data,
 		case 0xc0:
 		  node.first_cluster = grub_cpu_to_le32 (sec.type_specific.stream_extension.first_cluster);
 		  node.valid_size
-		    = grub_cpu_to_le32 (sec.type_specific.stream_extension.valid_size);
+		    = grub_cpu_to_le64 (sec.type_specific.stream_extension.valid_size);
 		  node.file_size
-		    = grub_cpu_to_le32 (sec.type_specific.stream_extension.file_size);
+		    = grub_cpu_to_le64 (sec.type_specific.stream_extension.file_size);
 		  node.have_stream = 1;
 		  break;
 		case 0xc1:
@@ -1026,6 +1026,8 @@ grub_fat_label (grub_device_t device, char **label)
   if (! data)
     return grub_errno;
 
+  *label = NULL;
+
   while (1)
     {
       offset += sizeof (dir);