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ubuntu, corrupted MBR - How to restore system


I have the following:

 * An ubuntu netbook remix iso installed on a bootable usb
 * a hard disk with a corrupted MBR.

What I want to do:

* Is boot off the hard disk using the kernel on the usb stick so I can get important data off it
* is fix the MBR

Further Information:

* the bootable usb uses SYSLINUX
* I can modify install packages on the bootable usb to help with the task if required
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1 Solution
Deals with booting the system with a liveCD and then reseting the MBR on the hard drive.

If your install has grub-install/grub you should be able to use it as outlined in the earlier post to restore the MBR.
make sure to make sure to reference the correct partitions where /boot is setup.

Covers multiple application of MBR restore.
geldfeldAuthor Commented:

The second post of that thread was helpful. I am not out of the woods yet, though.

I seem to have downloaded 2 corrupted ISOs. When I boot of the usb I am able to mount them it seems that it is the filesystem.squashfs that has been corrupted in both downloads.  I have spent the last few days trying to reconstruct a working filesystem.squashfs from the stock ubuntu-10.4-netbook-remix.iso/casper/filesystem.squashfs.

This is a shot in the dark but I get a parse error for me sudoers file when I boot of the usb drive. I get dumped into the console without an ability to sudo. I can't mount the corrupted drive or do anything else.

I only need to get as far as a root shell so that I can use grub to restore the MBR as described in one of the answers to my intial question.  I can edit the squashfile on a working linux system.

I can not download another iso. Internet goes through a satellite backbone and bills are in excess of two hundred dollars a month for 1 GB download limit. I'd appreciate pointers. Thx.
get the http://www.damnsmalllinux.org/
a 50MB download.

You would then mount your HD partitions where grub-install and grub are.

The problem you may run into is if your UBUNTU install is 64 bit while the damnsmalllinux might be 32 bit and would likely not be able to run grub* commands if those are not included on the Damnsmalllinux distro.  
Do you have any other access to the net where you can download the ISO?  
This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.
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