I think there is another recent thread where someone's 596 was locking to region 1 and it was recommended that they set up the pc with 596 off(not in standby) and go from there.It took us 4 or 5 attempts to get it right but it will work eventually and it is worth it!!
One return at the end should be enough,it won't acknowledge the commands anyway as far as I know.Just disconnect and try one or two discs of different regions to confirm.
Manus

Mostly harmless. Comfortably numb.