Re: Bug#709097: grub-pc: Boot failure after updating to 2.00-14 - cannot find normal.mod, grub-rescue reports /boot empty

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

On 11.08.2013 15:53, Colin Watson wrote:
> Control: retitle -1 misdetects FAT-overwritten-with-ext2 as FAT
> Control: severity -1 important

> This is a pretty specialised (hence the severity downgrade), but
> interesting, corner case.  It appears that the partition in question
> used to be a FAT filesystem (specifically, a Dell Utility partition).
> It has been overwritten sufficiently that the fstype magic has been
> overwritten:
>
>    00000000  eb 54 90 00 65 6c 6c 20  38 2e 30 00 02 08 01 00  |.T..ell 8.0.....|
>    00000010  02 00 02 00 00 f8 86 00  3f 00 ff 00 3f 00 00 00  |........?...?...|
>    00000020  92 2a 04 00 80 00 29 1c  0a d9 07 44 65 6c 6c 55  |.*....)....DellU|
>    00000030  74 69 6c 69 74 79 00 41  54 31 36 20 20 20 10 00  |tility.AT16   ..|
>
How does something like that come into existence? Why would only part of 
BPB overwritten? The tools that I know either overwrite whole sector or 
don't touch BPB.
> Vladimir, could you elaborate on this?  Which mkfs implementations were
> involved here?
>
AFAIR it was some FAT images that are commercially distributed. AFAIR 
neither Windows nor Linux check this field.
> It seems questionable to me for GRUB to be quite this liberal.  Perhaps
> we can restore its previous strictness somehow without breaking the
> filesystems that Vladimir ran into?
>
> Thanks,
>