This guide provides a detailed overview of TCL firmware, why updates are necessary, and the correct procedures for downloading and installing firmware for various TCL models.
To download the correct TCL firmware, you need the (e.g., 55C825 , 65R635 , 43S434 ). Find it in three places: Download Tcl Firmware For All Models
You generally cannot. Roku controls the OS. If you need a manual update, you must contact TCL Support, give them your serial number, and they may generate a private download link for you if you are a developer or beta tester. This guide provides a detailed overview of TCL