If you do use up all the changes on your actual drive there are 2
possible ways to go without returning drive to manufacturer.
1. install new firmware onto the drive, you can get it for most drives
at http://forum.firmware-flash.com/portal.php this will generally
restore your drive and as with my drive can set it to region 0, so it
will play any DVD region.
2. there is also a small piece of software that can reset your drive
regions, i think it got it from same site