Typically uses an 8MB SPI Flash (GD25Q64 or similar).
Press and hold the on the TV panel (not the remote) and plug in the power cord. Download SIS231 P83 FITCO FLED FHD Mirror Firmware USB rar
Ensure you download from a reputable technical forum like Elektrotanya or dedicated TV repair communities to avoid malware. Typically uses an 8MB SPI Flash (GD25Q64 or similar)