Commit b349abbf authored by Maxime Ripard's avatar Maxime Ripard Committed by Tom Rini
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gpt: Fix the protective MBR partition size

According to the UEFI Spec (Table 16, section 5.2.3 of the version 2.4 Errata
B), the protective MBR partition record size must be set to the size of the
disk minus one, in LBAs.

However, the current code was setting the size as the total number of LBAs on
the disk, resulting in an off-by-one error.

This confused the AM335x ROM code, and will probably confuse other tools as
Signed-off-by: default avatarMaxime Ripard <>
parent b6b1b445
......@@ -342,7 +342,7 @@ static int set_protective_mbr(block_dev_desc_t *dev_desc)
p_mbr->signature = MSDOS_MBR_SIGNATURE;
p_mbr->partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
p_mbr->partition_record[0].start_sect = 1;
p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba;
p_mbr->partition_record[0].nr_sects = (u32) dev_desc->lba - 1;
/* Write MBR sector to the MMC device */
if (dev_desc->block_write(dev_desc->dev, 0, 1, p_mbr) != 1) {
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