When searching for undocumented commands on the Panasonic Ultra-BD player DP-UB242 in inadvertently activated a "lock" mode. Now the player refuses to eject the tray (both from remote and the button on the device), instead the LED blinks twice. So I assume that it is a restricted (dealer) mode, for allowing customers to play but not to change or steal the disc in the player.

Anyone knows how to get out of this mode? Of course, I have already tried the system initial reset.