If you want to have your disk as hda, then check that option in the config, rebuild a kernel, and update /etc/fstab, and /etc/yaboot.conf (don't forget to re-run ybin) to use hda instead of hdc Ben.
I've had the same problem. Fastest way for me to fix it was to only alter /etc/fstab and /etc/yaboot.conf with the help of Gentoo Live CD for PPC. Since I was unable to boot, hence unable to rebuild a kernel. New kernel has some really nice features for PBG4, like blinking white led for disk activity. Very nice. So to stick to 2.4.21-ben2 features, is it also possible to switch the Apple logo on the back of my screen on and off independently of my monitor? Thanks, Pander