I updated my desktop machine last night with YOU - remotely from my laptop and recumbant position on the sofa. It didn't reboot. So I had to hobble to the study and try to find out why not - it gets as far as the detecting the IDE drives and then does a panic with horrible messages scrolling past too fast to read. This was with 2.6.5-7.108 (the current update for 9.1). So I had to put back the 2.6.4 version from the 9.1 installation media.

I hope this doesn't mean that this machine is going to have problems with all new versions - machine dates from 2000: nothing terribly unusual about the IDE controllers or disks as far as I know.