Welcome to the most active Linux Forum on the web.
Go Back > Forums > Linux Forums > Linux - Software
User Name
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.


  Search this Thread
Old 05-15-2006, 04:03 PM   #1
LQ Newbie
Registered: Feb 2006
Posts: 3

Rep: Reputation: 0
Question Disk Geometry changed by GRUB causes XP boot failure

Hi All,
A Bug in Fedora Core GRUB intall causes the disk geometry to be modified from LBA to CHS Format.The partition table now has both CHS & LBA value.Linux ignores CHS values but Windows messes up failing to boot.
I'm experiencing the same trouble,due to which i'm not being able to boot windows,however linux can still boot.
original disk geometry had 255 number of heads initially and was changed to 16 after the partition was corrupted by Fedora
None of the solutions suggested to the problem:
Setting BIOS setting from auto to LBA or
 $ sfdisk -d /dev/hda | sfdisk --no-reread -H255 /dev/hda
is working in my case.
So, the only option remaining to me is to clear the MBR & partition table & rebuilt them again.
i plan to clear MBR using:
$ dd if=/dev/zero of=zero.img bs=512 count=1
$ dd if=zero.img of=/dev/hda
& rebuilt the partition table & MBR
Can i do this i rebuilt & restore original partition table without loosing valuable data & how?How to make a backup of partition table & MBR so that i can restore them if above process fails?
Thanks in Advance
Old 05-15-2006, 11:31 PM   #2
LQ Newbie
Registered: Feb 2006
Posts: 3

Original Poster
Rep: Reputation: 0
The data on my disk is very critical,so i don't want to make any irreversible change.
Old 05-16-2006, 08:07 AM   #3
Registered: May 2002
Location: central florida
Distribution: Linux Mint, ,Mageia,Ubuntu
Posts: 453

Rep: Reputation: 33
I am not an expert so take my suggestions with a grain of salt..
I would first suggest that you get your Linux distro to boot off a floppy or other device B4 making any changes..Edit you may have to reset your bios to boot off a floppy or other device "first boot device"..

Then you can use your windows XP install cdrom to fix the MBR..That will overwrite grub on the mbr..Do a google and learn how to
enter Windows the repair mode ..
That way you will be able to get into each distro..
Anyone else,feel free to jump in here to offer better advice..

Last edited by jolphil; 05-16-2006 at 08:10 AM.
Old 05-16-2006, 09:19 AM   #4
Registered: Feb 2006
Location: Australia
Distribution: Linux... :-)
Posts: 241
Blog Entries: 1

Rep: Reputation: 50
the only thing i can suggest is mount the ntfs and recover what you can...
if you can burn to cd then thats an advantage...
one other thing is i have changed bios settings without effecting the boot of linux but i'm not suggesting you do that first...get a backup of your work first then you may only have to re-install windows...
good luck...

Last edited by wraithe; 05-16-2006 at 09:21 AM.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Boot Disk Failure, Insert System Disk and Press Enter!! novkhan Linux - Hardware 1 12-15-2005 08:39 PM
More to FC2/XP dual boot bug than disk geometry settings? Curlychris Fedora - Installation 5 11-21-2004 04:52 AM
Boot problem w/FC2 - DISK BOOT FAILURE maugou Fedora 2 06-30-2004 07:37 PM
FC2 disk geometry (NOT double boot) ferrix Fedora 1 05-28-2004 02:22 AM
li error and boot disk gives boot failure message Mr.Scum Linux - General 5 05-20-2003 11:41 AM > Forums > Linux Forums > Linux - Software

All times are GMT -5. The time now is 08:54 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration