The only reason you would want to use cromwell is for linux, but you can still run linux with the other bioses. Most people do a split with the latest xecuter bios and the latest evox bios. In my opinion, the X2 4978.03 is the best bios out there, and for me, splitting my tsop with x2 4978.03 and evox d6 would have been pointless, so I flashed my other half of my tsop with a debug bios to run the developers stuff. Anyway, if the purpose of this is to be able to flash the other half in case one goes bad, then your best bet is to run andx2 bios and an evox bios.