@Hrududu: Guess you're one of the lucky ones. The IDE corruption is widely mentioned on xlr8yourmac with the Rev.1 boards. Plenty of ideas but none have worked for me so far. Can you tell me what drives you're using and how you have them cabled/jumpered? I'm not looking for a multi-drive setup, just one. I'm down to a 10GB Seagate here and it corrupts straight away. Still haven't managed to install an OS after 3 days. The drive is perfect, I've ran SMART and surface tests. The logic board checks out in MacTest Pro. I had 4x256 sticks of PC133 in it initially, but to rule them out I'm down to a single 64mb stick of PC100 and still no dice.

@Gorgonops: It was the 4.1 firmware. Moot point anyway as OS X Server didn't like it (no drives found). I was afraid something like that would happen but had to try it anyway. Tried to install it to the 10GB Seagate IDE but after a while of copying files it KP-ed with "ffs_clusteralloc: map mismatch".