Press and hold the button on the TV's physical side panel.
For advanced diagnostics or a factory reset after an update, you can enter the Service/Factory Menu: Press on the remote followed by the sequence 8202 . Download TOSHIBA 55U7750VN FIRMWARE part1 rar
If your TV is experiencing a "stuck on logo" or "boot loop" issue, use this method: Turn off the main power and unplug the TV. Press and hold the button on the TV's physical side panel
While holding the button, plug the TV back into the power outlet. Download TOSHIBA 55U7750VN FIRMWARE part1 rar
Select or OK to begin the process. The TV will automatically restart once finished. 3. Accessing Service Mode
Press on the remote and navigate to Settings > Software Update (USB) .