[ale] grub rescue

Derek Atkins derek at ihtfp.com
Sat Feb 18 17:19:27 EST 2012

A related question:  Where is your /boot partition?

Assuming you are using dm-crypt and LUKS, then most likely your /boot
would be unencrypted and your /root would be encrypted -- and it would ask
you for a password to boot up.  However I don't see a /boot partition. 
Was it part of the extended partition?

My guess is that your /boot partition is hidden somewhere in your extended
partition map and it got destroyed at the same time as your root
partition.  Or did you have a combined boot/root partition, in which case
I have to ask how it was encrypted?  But if you did have two partitions
then unless you want to spend lots of hours scrounging your disk to *find*
those partitions you may very well be out of luck.

Right now I highly doubt that any linux recovery is going to find your
data, because the disk would tell the system that "there ain't no data
here".   What I would do, before you go futzing with anything, is make a
complete backup of your disk.  Get another disk and do a dd from this disk
to the other disk.  Then you can start futzing with the partition tables
and, worst case, recover from the backup in case thingsdon't work out.  My
fear would be if you start futzing with the extended partition table and
get it wrong you might end up overwriting real data.

Once you make your copy, try making all your unallocated space into a
single linux partition.  Then you can dd the first few MB off into a file
(running a RAMDISK rescue environment, of course) and use 'file' to see if
you got it right.  Were you using LVM?  Then from there you might be able
to get lucky and find your partition endpoints.  But honestly, I suspect
you're going to have a hard time recovering if you had multiple partitions
in that extended space.

Good Luck!


On Sat, February 18, 2012 2:43 pm, Michael Trausch wrote:
> That's not going to help if the root partition is not in the partition
> table, though.
> Additional questions for the OP: what partitioning utility was used to
> create the partition? Also, you said that the partition was encrypted, but
> if that is the case I assume you had to give the system a key at boot time
> before the kernel could even be loaded, is that correct?
> --
> Sent from my Ice Cream Sandwich!
> On Feb 18, 2012 2:36 PM, "Mike Thornton" <mrmthorntonlinux at gmail.com>
> wrote:
>>  Try the command 'update-grub' .  If that doesn't fix it see
>> CreatBootPartitionAfterInstall<https://help.ubuntu.com/community/CreateBootPartitionAfterInstall>
>> ( https://help.ubuntu.com/community/CreateBootPartitionAfterInstall )
>> On 2/18/2012 2:09 PM, John Pilman wrote:
>> I am re-sending this because I don't think my last attempt at this
>> post was successful.  I apologize if you are receiving it twice.
>> I got in a hurry when my laptop was booting.  It dual boots Windows 7
>> and Ubuntu 10.10.  While
>> booting I bumped the keyboard and I think it started a Windows
>> Recovery partition.  I waited and then exited when presented with that
>> choice, now I get:
>> 'error: no such partition'
>> grub rescue>
>> The ls command returns:
>> (hd0) (hd0,msdos5) (hd0,msdos4) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1)
>> When I boot Ubuntu from a live USB and look at gparted I see:
>> /dev/sdb1  ntfs  PQMSERVICE                 13 GiB    diag
>> /dev/sdb2  ntfs  SYSTEM RESERVED   100 MiB    boot
>> /dev/sdb3  ntfs                                           94 GiB
>> /dev/sdb4  extended                                190 GiB
>> unallocated  unallocated                          185 GiB
>> /dev/sdb5  linux-swap                             5.86 GiB
>> I'm guessing my data is in the part marked unallocated.  Here's my
>> question:
>> Since I installed Ubuntu with encryption, would I be better off trying
>> to mount that partition and look for my data or
>> would you suggest I try to recreate or resurrect grub and its associated
>> table.
>> Also, I'm looking at trying 'testdisk' but the instructions tell you
>> to use the one for your OS.  I did not see specific instructions for
>> dual boot PCs.  Does anyone have a relevant hint here?
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       Derek Atkins                 617-623-3745
       derek at ihtfp.com             www.ihtfp.com
       Computer and Internet Security Consultant

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