I have tried the 1,6,7 code any it will play region1 also. Basically
switch on the unit. Press system on the remote. Press in the following numbers "167" then the screen will show "Region 1-6", then key in the region code you want the player to play. You have to go into this everytime you play a different region. I havn`t used the feature that often so I don`t know if the system locks up or not.