(Sorry to reply out-of-thread).

It seems that the firmware /was/ expecting a "pure" ISO9660 disc to boot 
from. I told Nero not to use any "relaxed" ISO restrictions when writing 
another CD and did:

boot cd0:/FLASH_X8.IMG

and it worked. :) Now the firmware is 1.3 and the board recognises the 20GB 
Maxtor properly.

Now all I have to do is install the OS. :)

Cheers,

Tim.