While holding the button, plug the TV back into the power outlet.
To download the firmware for the (often listed as LED43D2930), you generally need the USB update file specific to its chassis, which is typically the TP.MS6308.PB775 . This model is often serviced through third-party technical forums or Telegram communities rather than direct public links on the official TCL global site. Firmware Details Model: TCL L43D2930S / LED43D2930 Main Board / Chassis: TP.MS6308.PB775 Download TCL L43D2930S Firmware part1 rar
Press and on the TV (not the remote).
Continue holding until the "Upgrading" or "Software Updating" screen appears, then release the button. While holding the button, plug the TV back