Turn off your smartphone completely. Hold the Volume Down or Volume Up button (depending on the OEM), and connect the phone to the computer via the USB cable.
The safest way to get the correct MT6580_Android_scatter.txt file is to download the complete for your specific phone model. The scatter file is always included inside the extracted firmware folder. mt6580androidscattertxt link
The (SmartPhone Flash Tool) is the standard utility for flashing MediaTek devices. Here is the step-by-step process: Turn off your smartphone completely