cmd: gpt: backup boot code before writing MBR

On some cases the first 440 bytes of MBR are used to keep an additional information for ROM boot loader. 'gpt write' command doesn't preserve that area and makes boot code gone. Preserve boot code area when run 'gpt write' command. Signed-off-by: Vincent Tinelli <[email protected]> Signed-off-by: Brennan Ashton <[email protected]> Signed-off-by: Andy Shevchenko <[email protected]> Reviewed-by: Simon Glass <[email protected]>
grygoriyS · Feb 8, 2017 · e163a93 · e163a93
1 parent d726f22
commit e163a93
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/disk/part_efi.c b/disk/part_efi.c
@@ -324,6 +324,13 @@ static int set_protective_mbr(struct blk_desc *dev_desc)
 		printf("%s: calloc failed!\n", __func__);
 		return -1;
 	}
+
+	/* Read MBR to backup boot code if it exists */
+	if (blk_dread(dev_desc, 0, 1, p_mbr) != 1) {
+		error("** Can't read from device %d **\n", dev_desc->devnum);
+		return -1;
+	}
+
 	/* Append signature */
 	p_mbr->signature = MSDOS_MBR_SIGNATURE;
 	p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;