I'm having a similar issue as this. My flashing gets through just over half way, then freezes. I let it sit for a good 40 minutes, came back and it was in the same place. The xbox would flash orange, go dark, then flash green, repeating. I assume this was the generic 'Flashing' response. I havent tried any other X3 bioses, X2 or Evox bioses, but I'd like to know what the problem is. I'm pretty sure all my connections are good.
Btw, this was using 1-on 2-on 3-off 4-off 5(protect)-off for the bank to flash. I'd like to know what the problem is.. at least I can always use the backup bios to reflash.