Before you begin, you must properly format your flash drive to ensure the TV can read the update file. How to update the software on an Android TV - TCL Support
That evening, with Elena watching from the couch, Arthur knelt before the TCL. The TV was off. He unplugged the ethernet cable (just to be safe) and inserted the USB into the blue port—the service port, the forum said. Tcl Tv Software Update Usb