Once the light stops flashing or changes color, unplug the USB drive and restart the device.
Use a USB flash drive (ideally 2.0 and 8GB or smaller) and format it to FAT32 . Download 3663LUA A81 1280x768 Firmware USB rar
Extract the downloaded .rar file and copy the .bin firmware file directly to the root directory of the USB drive (do not put it in a folder). Once the light stops flashing or changes color,