This is what I do to flash.

1. Cleaned and formatted to FAT32 file system the USB drive
2. Stick the USB drive to one of the port behind the box.
3. Power on the unit
4. Red LED at the box and the box stuck there.
5. No display on the 2" LCD and on the tv.
6. USB stick keep on flashing.
7. Repeat the steps above using another USB stick. A total of 5 USB sticks I used to flash the box. Nothing happens.