– Use 7-Zip or WinRAR. You should see files like preloader.bin , boot.img , system.img , and scatter.txt .
Keep it at at least 50% battery to prevent it from shutting down during the process. firmware zte blade a51 hot
Power off. Press and hold until the ZTE logo appears, then release Power but keep holding Volume Up. – Use 7-Zip or WinRAR