Comment 13 for bug 154697

I can add some more details now:

The first installation failed, giving first a non-fatal error about cupsys upgrade, then crashing in the process of writing the kernel image!!! Clearly, this left me with a non-working 2.6.22 (generic) kernel. I had to restore the partition from the image I made (PartitionImage + Knoppix saved my life, I strongly advice this combination!!!).

Then I tried again and it worked just fine.

Differences between the first and the second time were:
1) The second time I did activate cupsys before upgrading, since I read in another bug report that having it turned down was a cause of failure
2) Maybe more important, I avoided uninstalling the nvidia drivers. Those were installed through the "envy" script. The first time I removed them as adviced on the envy website, and I did also purge compiz (which I had from the git repository). The second time I left everything as it was, and all I had to do at the end was downgrading some compiz packages which had not been overwritten by the upgrade (ccsm and a couple others).

I hope this helps.