it being sony, the've probably done it so that it can run a certain iso with a certain compression and certain security.
Sony arnt that dumb.
I guess it's like the psx loader. Can only run signed games which only work on the console it was purchased for, so it wouldn't do people on 3.51 any good (other than being able to purchase downloadable games).
well i think we can all be sure that sony has added sercurity but i have a small feeling that in the coming months the tools used to compress them or add sercurity might be leeked :D
or heres an idea i wonder how theyre going to stop people downloading games and then reuploading them to their own sites
probably by like making you download it from the psp and saving you mac address or serial or something but im sure a way well be found to change the serial using reverse engineering