Installing on a powermac with no primary disk results in boot problems

I tried installing the latest Kubuntu on a 1GHz G4 PowerMac which has had its
main hard drive transfered onto another IDE cable. That is, the disk that Open
Firmware called "hd" was moved so it was called "ultra2". The installer worked
nicely with no errors but booting failed. I ended up booting from the live cd
and fixing yaboot's configuration manually. I eventually got it to find the
kernel image but the kernel paniced due to failure to find init. I went on to
try diffrent root= boot parameters and eventually got it to boot. Then I noticed
the root= paramenter I had given was diffrent than the root file system listed
in fstab. I don't have access to the machine now so I cannot tell you which was
/dev/hdc and which /dev/hda but there was obviously some confusion about what
the disk was to be called.

I tired logging in to KDE but it hanged when trying to detect devices.

I had this exact same problem when I tried Ubuntu Hoary on the machine earlier.
Interestingly the Kubuntu Live-CD works perfectly. The machine also had a CD
drive and another hard-disk but at the time it didn't occur to me to check out
how they were connected or what they were called.