Copy the extracted firmware file (usually named V8-xxxxxx.bin or MstarUpgrade.bin ) directly to the root directory of the USB—do not put it inside a folder. : Turn off the TV and unplug the power cord. Insert the USB drive into the TV's USB port. Press and hold the Power button on the TV (not the remote).
Wait for the progress bar to reach 100%. The TV will usually restart automatically. Download TCL LED40D2939 Firmware part2 rar
While holding the button, plug the TV back in. Keep holding until the "Software Upgrading" screen appears. Copy the extracted firmware file (usually named V8-xxxxxx