I think it must be a modification of the param.sfo file. Connect via pc to the console, extract param.sfo and once modified overwrite the existing one in the console, before executing it. (I don't know how to modify it, maybe it's a question of proof and error) If the author doesn't have an exploit for higher firmwares, that's one of the possibilties.



Another one could be to use the payload found in 1.76 to spoof the firmware. This payload could modified in order to make it work in 4.05



those people with a console in 1.76 could try to dump a game with a highter firmware, using that payload.