Sony's ongoing battle with PSJailbreak seems to have reached the software side, as DigitalFoundry reports that Medal of Honor requires at least PlayStation 3 firmware 3.42 in order to run. DF notes that copies of the Medal of Honor have made it onto the net but "the game is completely unplayable with the hack as is." It seems that 3.42 includes a new decryption key, which is required to run Medal of Honor, while the firmware that PSJailbreak is based on "simply can't read the code." Presumably, this protection will be added to other future releases as well.
The article adds that it's possible that existing hacks could be altered to accommodate the change, though it remains to be seen if that will happen and, if so, how long it will take the hacking community to adapt.