: Ensure you have the Scatter File for your exact model. Using a scatter file from a different device, even with the same MT6781 chip, can permanently brick the phone.
A tool that disables the "Serial Link Authentication" and "Download Agent Authentication" parameters. mt6781 sp flash tool exclusive
Wait for the utility to show "Protection disabled" or a similar success message. : Launch flash_tool.exe as an Administrator. : Ensure you have the Scatter File for your exact model