[U-Boot] [PATCH v1] DOS_PBR block type is also valid dos block type.

[Stephen Warren]

On 03/15/2013 12:36 AM, Sonic Zhang wrote:
...
> We can erase the first 3 blocks completely before formatting it again.
> But, nothing can prevent others from formatting the SD card with
> different tools.

Surely any tool that creates a partition table on a device when there
wasn't any partition table there before (i.e. converts a raw filesystem
to a partition table) should zero out the "boot code" area of that MBR,
since there is no "boot code" area in a raw filesystem. This seems like
a bug in whatever partitioning tool was used.

If any device /always/ historically contained a real partition table, or
/always/ contained a raw FAT filesystem, then there will be no issue.
It's only when switching between the two, and not clearing out all the
data in the MBR when doing so, that you get this problem.