Grab your Mi Remote. Press and hold the and Manual/Apps buttons (or OK and Back buttons, depending on your remote variant) simultaneously.
This error occurs if the downloaded firmware file is corrupted or belongs to a different Mi TV model. Double-check that the file you downloaded matches the model identifier precisely. Firmware Update on XIAOMI Mi TV 4X 43 L43M4-4AIN
Place the firmware file in the root directory of the USB drive. Grab your Mi Remote