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Published 20 hours ago • verified publisher icon raspberrypi

Early CM3 versions when booting from eMMC require boot partition to be FAT-32 (but can be FAT-16 from USB)

Open nunojpg opened this issue 3 years ago • 1 comments

Hi,

After extensive debug including attempting old and new bootcode I reached this conclusion:

Boot from FAT-16:

Not possible:

  • Some CM3 boards from eMMC

Possible:

  • The same boards from USB
  • Most CM3 boards
  • All CM3+ boards

The issue workaround is to use a FAT-32 partition instead.

This points to a ROM silicon bug, particularly considering they boot from the same image from USB but not from eMMC. I question if this is known, maybe possibly fixed by firmware, or if the OTP program_emmc_boot has anything to do with this.

nunojpg avatar Aug 11 '22 10:08 nunojpg

All Raspberry Pi OS images use FAT-32 with either 1 or 4 sectors per cluster. For maximum compatiblity I would suggest using that. We'd need exactly details of the FAT image (i.e. a dump for the boot-partition) to say for sure but I'm not aware of FAT specific fixes in the ROM (although they could predate my knowledge!)

timg236 avatar Aug 11 '22 13:08 timg236