Is the 720p video out a hardware or software limitation?
No Software Limitation of P96, 1080P was already shown working with V2, but only at 24hz (and it's not fast, takes a fair chunk out of mem and cpu performance)
720P is pretty optimal also on v2 it runs nice&fast for me.
It's a bit of a hard read with irc log, but to start trouble shooting.
When you have no boot devices connected (gvp and cf card adapter disconnected) do you see the vampire boot logo on the HDMI output and does it give a stable picture ?
It seems your vampire is working just fine. Problem is with these old games and demos is that they cannot handle a really fast 68K such as the vamprire. Most old games/demos also do not run out of the box on a 040 or 060 because of the same problem. For this WHDload was invented 8-) But also WHDload...