weired problem around grub2

[Geronimo <geronimo013@arcor.de>]

Hello,

I had to reorganize some of my partitions, cause space requirements changed 
during lifetime of that machine.

I thought - not a big thing - saved backups of each partition and started 
repartitioning from a live system. Then I decided to change fstype from ext3 
to ext4 and restored the backups.

Things work fine except grub2.

I was not able to reinstall grub2 to the restored system.

So I installed a new debian on another partition of the same disk (beside the 
old root) with similar configuration. There grub2 works without problems.
My old/restored root was recognized and I'm able to boot that system from grub 
installed to the new system.

The point is - the new system should be deleted - I want to install windows to 
that partition. So I need to install grub2 on my restored root partition.
But whatever I try - grub will not work with that partition.

I copied devices.map from the fresh system and run grub-install, which seems 
to work, but on reboot grub hangs without showing the menue.

As there's no problem booting debian from restored root, when grub is 
installed to the fresh installation, I guess, that the change of the fstype is 
no problem.

When I boot from debian CD  into rescue mode, selecting the recovered root as 
root and try to reinstall grub2 - the installer breaks, telling that it is not 
possible to install grub2 to that partition.

Any hint, how I could recover grub2 on the restored rootfs?


kind regards

Gero