Changing eMMC boot partition size

8 Nov 2022


      Hi everybody,
I have a question regarding changing the eMMC boot partition size.
According the the JEDEC eMMC spec it is read-only (BOOT_SIZE_MULT
register).
But we still have mmc_boot_partition_size_change() in
drivers/mmc/mmc_boot.c. It contains the comment
/* Only use this command for raw EMMC moviNAND. Enter backdoor mode */
What is moviNAND? My research pointed me to Samsung products only. So
is changing the boot partition size vendor specific or can it be used
more generally?
To be specific, I use the Kioxia THGBMJG6C1LBAB7 eMMC chip.
Thanks and best regards,
Philip Oberfichtner