diff --git a/disk/part_dos.c b/disk/part_dos.c
index 046f9bbb3d697dccf702d263d9d0cd15f00b0a68..9dd086d3db0610d966f446b0f3ea350de9a71f57 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -90,7 +90,7 @@ static int test_block_type(unsigned char *buffer)
 static int part_test_dos(struct blk_desc *dev_desc)
 {
 #ifndef CONFIG_SPL_BUILD
-	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, dev_desc->blksz);
+	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, 1);
 
 	if (blk_dread(dev_desc, 0, 1, (ulong *)mbr) != 1)
 		return -1;