Well this one is posted on VideoHelp... however I would be wary of the 'Play 159' handset hacks, since on older models you only get 25 changes and then the unit becomes locked to the last region selected.
- GOTO Browser
- Place the cursor to HDD (Highlight HDD)
- Use the Remote control
- Press 'PLAY' 159 121212005255 'PLAY'
- Goto Standby
- Start the unit again
If thgis works, get back to us and there's a better option for unlimited changing of regions (useful for RCE locked DVDs, that is).