[TippeX]

well, the cdcheck is done from timing looking at duplicate sector reads (thats why you can't burn an image), in game there's also checks which read a good sector (cracked will read bad sector), and the game acts on that, theres a bit of difference in the versions too, but all the reads and checks are via deviceiocontrol (possibly 'masked' inside the vm code).. so dumping at the oep isn't the end, rather it might be mid way through.. depending on the protection settings