Because TCL’s website does not always provide public download links for these specific bin files, it is recommended to contact the TCL after-sales team if the community files do not work. They can often provide a direct link to the correct software based on your serial number.
Public archives have cataloged specific dump files for this model and its chassis (TP.MS1306.PB775): Download FLASH DUMP TCL L40D2900 rar
Press and hold the on the TV (not the remote). Because TCL’s website does not always provide public