[Cialug] Recover fat32 logical partition(s)

[Jonathan A. Kollasch]

On Fri, Jan 31, 2020 at 02:56:12PM -0600, L. V. Lammert wrote:
> Just lost an old system, .. looking at the HD, I see:
> 
> 	/dev/sdb1	*	FAT32
> 	/dev/sdb2		EXT'd (LBA)
> 	/dev/sdb5		FAT32
> 
> The weird part is that sdb1 shows bootable, yet there are no system files
> there and sdb5 is a backup partition.
> 
> So, .. there are two partitions missing - the system partition and the
> main data partition. None of those files show up in 1 or 5. In addition, 2
> and 5 are exactly the same sectors.
> 
> Seems like the extendition partition(s) entry is corrupt?
> 
> Starting a sector by sector now, any recommendations on how to rebuild the
> partition table?

I know utilities exist that scan for Linux Ext2+ and *BSD FFS/UFS based
on signatures, I'd bet something similar exists for FAT.

It's not particularly weird to see partition 2 and 5 at the same sector,
an MBR and PBR aren't necessarily mutually exclusive, and extended MBR
is basically just putting a MBR in a PBR.

	Jonathan