[SOLVED] GRUB-PC installation error in a botched hard disk

nicolas_lz · 08-21-2011, 04:24 PM

Hello everyone!

I have a trouble when I try to install grub-pc in my hard disk, I get this error message:

Quote:

/usr/sbin/grub-setup: error: /dev/sda appears to contain a udf filesystem which isn't known to reserve space for DOS-style boot. Installing GRUB there could result in FILESYSTEM DESTRUCTION if valuable data is overwritten by grub-setup (--skip-fs-probe disables this check, use at your own risk).

/dev/sda is not an optical device, it is a Serial ATA hard disk. It happened after a huge mistake I made yesterday: I accidentally deleted the partition table of that HD filling with zeroes the first part of the disk. Yeah, using the "dd" command in the wrong device :P

Luckily, I recovered almost all of my partitions using TestDisk (http://www.cgsecurity.org/wiki/TestDisk), but since then I get the "udf filesystem" error when I try to install grub on it. I suppose there might be some zero-filled bits over there, and Grub didn't expect it.

I've tried with grub-pc versions 1.99~rc1-13ubuntu3 (Ubuntu 11.04) and 1.99-11 (Debian Unstable). I've got a x86-64 processor and a Western Digital WD2500AAJS-0 hard disk, 250GB.

Does anybody knows how to fix it?
Thanks in advance!

PD: I am using a Live CD with Xfce Desktop, and Thunar displays the partitions of the hard disk as "UDF volume"...

andrewthomas · 08-21-2011, 06:59 PM

I have not tried this, but it seems that it may work.

Quote:

Originally Posted by http://nitinpant.hubpages.com/hub/Repair-Partition-Table

All you have to do with Gparted to fix the broken partition-table is to do some changes like edit or shrink a partition, create a new one out of existing space or so.

http://nitinpant.hubpages.com/hub/Re...artition-Table

syg00 · 08-21-2011, 10:22 PM

What does "fdisk -l" (as root if necessary) show - from a terminal on the liveCD.

nicolas_lz · 08-21-2011, 10:33 PM

andrewthomas, unfortunately, it didn't work for me. I only could try gparted because the only partition I couldn't recover was the Windows installation (I don't care about it). Thanks anyway!

syg00, this is the output of fdisk. Thanks for your help.

Code:

$ sudo fdisk -l /dev/sda

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0004cec6

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        9961    80010240   83  Linux
/dev/sda2   *        9962       20550    85056140   83  Linux
/dev/sda3           20551       30273    78099996   83  Linux
/dev/sda4           30274       30402     1030144   82  Linux swap / Solaris

now, sda1 is just an empty ext3 filesystem. I had a Windows installation here before I deleted the partition table.
sda2 is for Debian
sda3 is the /home directory
sda4 is swap

syg00 · 08-21-2011, 10:53 PM

Not making too much (more) sense - that looks o.k. except for the 2 boot flags; delete one or both.
Go here, do what it says, and post the RESULTS.txt. Has all your (current) boot/partition info.

nicolas_lz · 08-22-2011, 01:14 PM

Here you have the RESULTS.txt file: RESULTS.txt

Now, the name of the troubled device is /dev/sdb, because I added another hard disk with some personal documents, and it took the "sda" label.
Also, I've tried using LILO and it worked! (GRUB still doesn't). However, I would like to know what happened to the drive.

Thanks you!

syg00 · 08-22-2011, 07:07 PM

Normally that contains a hex dump of the MBR - those decoder errors may indicate your guess above is correct.
Grub classic handles zeroed disks fine - must admit I haven't bothered testing grub2; still not much of fan of it.

If he grub-install still doesn't work open a bug report against it.

nicolas_lz · 09-02-2011, 01:44 PM

Hi again! Luckily, I've solved it. For some reason (testdisk, maybe?) I had another partition table in /dev/sda1 device. I just made a backup of the disk contents (I had to buy another HD), then I zeroed again (now, intentionally) the first part of /dev/sda, I created the partitions again and restore its contents from the backup.

Grub worked again, "and they lived happily ever after"

Thanks for your help!