Did you find a solution for this? It also happens on the boss hacked version for me btw.That's odd. The modified version just patches the unlock codes in so you don't have to input them (YAMAAOUT and MORIKAWA in the test menu). I'm pretty sure I had both of those done.
Anyway, happy to hear you got it working. I'll have to try it out sometime.
Then I think it has to be I/O related. Let me see which revisions I have in both machines.Yeah I tried both on my netboot setup and it just locks up inputs on both versions. This happens only on CVS2 for me!