I've posted about this in another thread, but maybe this deserves its own thread (not to mention probably NOBODY will see my other post - the thread is moving far too fast).
I just tried to run WWE Smackdown! vs. RAW 2006 on the custom firmware, and it will not start. It runs the SCEA gameboot, the UMD spins, then abruptly stops. The PSP returns to the XMB (sorry Firey - Typing Impared) stating: "The Game Could Not Be Started (8002012D)"
I tested a bunch of my other games, ranging from Untold Legends to The Godfather (pretty much games requiring every firmware between 1.50 and 2.71) with no other issues. UMD Video seems to work (tested Hellsing), as does everything on my original sampler disk.
So, any other games not working? Let's get a list started so the troubleshooting can begin!
Thanks again Dark_AleX - looking forwards to a patch of this issue!