@TiredOfLife

Effectively, it could be a problem of monitor drivers. I've already had this kind of problem with my old configuration: A1200PPC + BVision + Mediator + Voodoo 3000 + SB128. The Voodoo graphic card was only used by the SB128 card (for memory access). I don't really remember what I've precisely done to fix that problem, but I think I've modified the kicklayout file to comment out some graphic drivers (it accelerates the firs boot)

But I have had another problem: in the past, I've tried to use a Grex bus on my 1200 and was obliged to flash my Blizzard PPC ROM. The GREX has never worked because of the revision of my PPC. When I installed the OS4 for the first time, I've had big difficulties to use the BVision display (OS4 was booting on Aga display and disk access was extremely slow). I've discoverd, then that it was bound to the flash update...

(Sorry for my bad french english too...)

@doraemon

You should maybe put a "set echo on" on your startup sequence, just to see where it blocks and add the verbose option to your bootloader command.

...it could be, for instance, a problem with your network connection.