Not for all SoCs the bootloader start at offset 0x0, in a hardware partition of an emmc. So we need the possibility to set the correct offset, where bootloader starts.
Example: imx8qxp revision C0 emmc Partition layout | eMMC block / partition | Offset | Size | Purpose | | ---------------------- | ---------- | ----- | ------------------------------ | | /dev/mmcblk0boot0 | 0x0 | 2MB | imx-boot-container A | | | 0x00220000 | 128kB | secure boot signature rootfs A | | /dev/mmcblk0boot1 | 0x0 | 2MB | imx-boot-container B | | | 0x00200000 | 8kB | U-Boot env 0 | | | 0x00202000 | 8kB | U-Boot env 1 | | | 0x00220000 | 128kB | secure boot signature rootfs B | imx8qxp rev B0 emmc Partition layout | eMMC block / partition | Offset | Size | Purpose | | ---------------------- | ---------- | ----- | ------------------------------ | | /dev/mmcblk0boot0 | 0x00008000 | 2MB | imx-boot-container A | | | 0x00220000 | 128kB | secure boot signature rootfs A | | /dev/mmcblk0boot1 | 0x0 | 8kB | U-Boot env 0 | | | 0x00002000 | 8kB | U-Boot env 1 | | | 0x00008000 | 2MB | imx-boot-container B | If we flash now the bootloader image flash.bin on a B0 revision with uuu FB: flash bootloader flash.bin we overwrite the environment and board does not boot at all, as offset is wrong. To prevent any API change in the above command we propose the following implementation from this series: We add a new weak function fb_mmc_get_boot_offset() in drivers/fastboot/fb_block.c which returns 0 and call this function instead of passing 0 for the offset where offset is used/passed. In SoC specific code (currently for IMX8QXP only) we implement this function that it returns on B0 SoCs the 32k offset and on other SoC revisions the offset 0. This is tested on B0 and C0 based boards from siemens. This patch should have no effect for other SoCs. Changes in v2: - added Reviewed-by from Mattijs - Used the commit message as Peng suggested (with a small checkpatch fix: WARNING: 'writting' may be misspelled - perhaps 'writing'? - rebased to mainline b99da05e153 - (tag: v2026.04-rc2, origin/master, origin/HEAD) Prepare v2026.04-rc2 - added Reviewed-by from Mattijs Adrian Freihofer (2): fastboot: mmc: make boot partition offset configurable arch: imx8qxp: Override weak fb_mmc_get_boot_offset function arch/arm/mach-imx/imx8/cpu.c | 21 +++++++++++++++++++++ drivers/fastboot/fb_block.c | 15 +++++++++++---- 2 files changed, 32 insertions(+), 4 deletions(-) -- 2.20.1 base-commit: b99da05e1538b8fa153322da82917af2aa27e1d6
