While holding the button, plug the TV back in. Continue holding until the LED light begins to blink or an "Upgrading" message appears on the screen.

Updating a TCL TV via USB is a reliable alternative when network updates fail or when a TV is not connected to the internet. This report outlines the preparation, execution, and troubleshooting steps for a successful manual firmware update.

: A drive with at least 4GB to 8GB of space is recommended. 2. Update Procedures by TV Type For Google TV and Android TV Models

mojothemonkey2/TCL_Guide: Docs to help with TCL ... - GitHub

He examined the TV. The screen now showed a single line of text in the corner, like a debug console: INTEGRITY VERIFIED. ROOT ACCESS GRANTED.