Comment 4 for bug 441941

Revision history for this message
Felix Zielcke (fzielcke) wrote : Re: [Bug 441941] Re: grub fails after running Windows

Am Mittwoch, den 14.10.2009, 11:06 +0000 schrieb JohnL:
> the problem is definitely with grub2 / 9.10 and not some other random
> Windows thing.

Just 2 days ago someone reported the same problem in Debian:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=550702

He confirmed that something in his Windows overwrites some stuff in the
embeding area (i.e. the sectors between MBR and first partition)

Please do the same things I told in message #20 there.

Check with fdisk -lu at what sector the first partition starts at.
Usually this is 63
Save the embeding area when you recovered GRUB 2 to sda.1 with e.g.
dd if=/dev/sda of=sda.1 count=63
Then boot Windows and then some LiveCD or your Ubuntu with a rescue disk
or something like that.
And do it again but this time use of=sda.2

To see the difference you could then e.g. use
diff -u <(hd sda.1) <(hd sda.2)

GRUB 2's core.img is much bigger then GRUB Legacy's stage1.5.
Seems like some Windows thing doestn't use the first part of the
embeding area but something in the middle or end of it.

--
Felix Zielcke
Proud Debian Maintainer and GNU GRUB developer