You can typically find this firmware on enthusiast forums, technical blogs, or through sellers on platforms like AliExpress .
Power on the board. The indicator light (usually on the 7-key button board) will flash red and blue. Download M3663 1440x900 General rar
Copy the .bin file directly to the root directory of the USB drive (not inside any folder). Flash the Board: Power off the TV board. Insert the USB drive into the board's USB port. Plug in the control keypad. You can typically find this firmware on enthusiast