Sorry for reviving,
Though just saw this and decided to leave an instruction here in case someone else need this.
>You have to enter its service mode option, to do a factory reset. There are two methods to reset. The first is simple to do; a Hard Reset. The other is somewhat skilled; is a Factory Reset (System Reset). To make it a hard reset, just unplug the device from AC mains wall socket, and re-plug it back after 15 minutes or so. If you do this by overnight is better.