If the downloaded file is a .rar file, you must unpack it using software like WinRAR on a computer to obtain the .bin firmware file.
Are you doing this to or just to upgrade ? Download TCL L40D2900 Software rar
The TV will automatically restart when the update is complete. Do not turn off power during this process. Important Notes If the downloaded file is a
Always ensure the firmware matches your board platform (TP.MS1306) to avoid "bricking" the TV. Download TCL L40D2900 Software rar
Copy the .bin or .zip file directly to the root directory of the USB drive (not inside a folder). Turn off your TCL L40D2900 and remove the power cable from the wall. Insert USB: Plug the USB drive into the USB port on the TV.