bug#33389: parted not recognizing partitions in "non-standard" MBRs with valid partition tables

On Thu, Nov 15, 2018 at 12:27:02AM +0200, Marc Stenson wrote:
> Hello,
> 
> While parted 2.3 had no issues with whatever was in the first 446 bytes of
> the MBR and only looked at the partition table, newer versions such as 3.2
> seem to be thrown by unusual boot code (e.g. Grub4DOS) and either show the
> entire disk as unallocated space or as one big volume/partition with the
> file system of the first volume. This is despite the partition table being
> fully compliant and happily read by fdisk and sfdisk.
> 
> This may be a "feature" rather than a bug.   Please pardon my ignorance,
> perhaps newer partition table schemes require the first 446 bits to be
> parsed.  However it could save someone many hours of frustration if this was
> noted prominently in the documentation.
> 
> In my case It was fixed with a simple:
>   dd if=/usr/lib/syslinux/mbr/mbr.bin of=/dev/sdb bs=446 count=1
> after taking the requisite backups and a deep breath.

Can you explain steps to reproduce this, or post the first 1M of your
disk someplace?

-- 
Brian C. Lane (PST8PDT)