cmd: mvebu/bubt: move eMMC data-partition uboot from LBA-0 to 4096

A38x bootrom only searches 2 sectors when booting from eMMC,
irregardless of data or boot partition: 0 & 4096.

For eMMC boot partitions sector 0 is fine, but on data partition it
conflicts with MBR.

Change bubt command default to 4096 for eMMC data partition only, to
allow using an MBR partition table on the eMMC data partition while also
booting from it.

Signed-off-by: Josua Mayer <[email protected]>
Reviewed-by: Stefan Roese <[email protected]>

Author: Josua-SR

cmd/mvebu/bubt.c

@@ -240,9 +240,16 @@ static int mmc_burn_image(size_t image_size)
 #endif
 
 	/* SD reserves LBA-0 for MBR and boots from LBA-1,
-	 * MMC/eMMC boots from LBA-0
+	 * MMC/eMMC boots from LBA-0 and LBA-4096
 	 */
-	start_lba = IS_SD(mmc) ? 1 : 0;
+	if (IS_SD(mmc))
+		start_lba = 1;
+#ifdef CONFIG_SUPPORT_EMMC_BOOT
+	else if (part)
+		start_lba = 0;
+#endif
+	else
+		start_lba = 4096;
 #ifdef CONFIG_BLK
 	blk_count = image_size / mmc->write_bl_len;
 	if (image_size % mmc->write_bl_len)