Do not power off the TV or remove the USB until the flashing stops or the TV restarts. This usually takes 3–5 minutes. 3. Alternative (Manual Menu Method) If the TV still turns on and has a working menu: Go to Settings > System > Software Update . Select Update by USB .
Sites like Kazmi Elecom often host these specific universal board files if you are missing any parts. Download MT5507 PB801 1920Г—1080 REF48 USB part4 rar
Ensure the power does not cut out during the update, as this can permanently "brick" the motherboard. Do not power off the TV or remove