How do you unlock a Sony DAV DZ660 to make it region free?

To unlock a Sony DAV DZ660 for region-free playback, you typically need to enter a specific code using the remote control. Start by pressing the "Setup" button, navigate to the "Preferences" or "Settings" menu, and look for the "Region Code" option. Enter the code "12345" or "00000" to unlock the region settings. If this method does not work, consider looking for dedicated software or hardware solutions that may be available online.