Keep your phone's battery capacity above 60%. A sudden power loss mid-flash will ruin the system partition layout.
The tool bar at the bottom will shift through yellow and red progress indicators as the firmware write operation completes. Once a green checkmark graphic appears, the process is successfully finished. firmware tcl 50 5g link
Extract the downloaded file to an easily accessible folder on your PC desktop. Extract the SP Flash Tool ZIP archive. Keep your phone's battery capacity above 60%