Bug#591416: This bug might be due to Windows programs overwriting grub

[Colin Watson]

On Tue, Aug 31, 2010 at 05:27:59PM +0200, Svante R Signell wrote:
> As revealed lately booting to Windows can cause parts of grub
> overwritten by Windows programs.
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=550702
> https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/441941
> 
> I think this happened to me after a Windows XP session. I didn't react
> too much then, since grub booted into Linux and then grub-pc was
> upgraded by a new version. Missing boot menu might be due to some
> program overwriting the "embedding area". Now I'm reluctant to boot to
> Windows until this problem is solved. The problems seen are similar as
> the Ubuntu bug:
> https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/601563 where no
> boot menu is shown at all, but Linux boots automatically.
> 
> Pleas let me know if I can help in any way to find which program is
> overwriting grub.

Can you provide the specific data I requested in my blog post?  Namely:

 * Save the output of 'fdisk -lu' to a file.  In this output, take note
   of the start sector of the first partition (usually 63, but might
   also be 2048 on recent installations, or occasionally something
   else).  If this is something other than 63, then replace 63 in the
   following items with your number.

 * Save the contents of the embedding area to a file (replace '/dev/sda'
   with your disk device if it's something else): 'dd if=/dev/sda
   of=sda.1 count=63'

 * Do whatever you do to make GRUB unbootable (presumably starting
   Windows), then boot into a recovery environment.  Before you
   reinstall GRUB, save the new contents of the embedding area to a
   different file: 'dd if=/dev/sda of=sda.2 count=63'

 * Follow up with these three files (the output of 'fdisk -lu', and the
   embedding area before and after making GRUB unbootable).

Thanks,

-- 
Colin Watson                                       [cjwatson at debian.org]