However, I can help you write a about approaching such an update safely, which you can adapt once you confirm the actual device and source of firmware.
The update ZIP is not signed by the manufacturer, or you have a custom recovery (TWRP) expecting a different signature. Solution: Re-download the file from an official source. If using stock recovery, enable “Allow unsigned updates” if available (rare). Otherwise, flash using a signed package only. tp.sk518d.pb802 software update
Power off the device completely.
Turn off the TV and unplug it from the power source. 2. Update Process TP.SK518D.PB802 SOFTWARE However, I can help you write a about