Bug#333720: grub: Has shift primary partition table 16 bytes

Paul Frederiks paul.frederiks at zonnet.nl
Thu Oct 13 11:45:35 UTC 2005

Package: grub
Version: 0.95+cvs20040624-17
Severity: normal

I have installed Debian Sarge on a USB 2.0 HDD. It is a Lacie 200GB
disk.  dmesg reports this on the disk itself: Vendor: Maxtor    Model:
6B200P0 I am using it for more than 4 months now, to do backups and have
the same Sarge environment no matter which PC I'm at. Tuesday I had a
hard crash, requiring me to use the reset button. After this event the
disk failed to boot and couldn't be read by my main desktop machine
(that is running Sid recently). Apparantly the MBR was damaged. Using
information gathered from the internet I managed to rebuild my primary
partition table using a hexeditor. fdisk, cfdisk, parted and sfdisk
weren't up for the task and complicated matters further. After learning
about 0xAA55, CHS, sectors, 0x83, 0x82, gpart (guesses possible
partitions, it gave way to many results, but helped a lot) little endian
etc. I managed read my data again.  fsck gave no errors. It seemed
plausible only the MBR was damaged. Rebooting into the disk using a
Grub-floppy nothing seemed wrong. So it was time to reinstall GRUB onto
the disk itself.  grub-install /dev/sda resulted in a complained about a
failure to read /boot/grub/stage1. While surfing for answers what this
means I experienced another complete system crash. After resetting the
MBR was damaged again. Now used the hexeditor immediately and noticed
that the primary partition table was shifted 16 bytes. It was replaced
by GRUB code. I'm attaching a dump of the first to sectors of the disk.
If it isn't a GRUB bug, please give me pointers on solving this!

Paul Frederiks

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