Step 1. Download SP Flahs Tools here.
Step 2. Download MTk ADB Driver here.
Step 3. Extract driver, and also SP Flash Tool.
Step 4. Install ADB Driver
Step 5. Run SP FlashTools, click “Scatter-loading” choose scatter for your device then click “Format”, then choose Auto Format Nand Flash –> Format Whole Flash, then click OK.
Step 6. Plug USB cable to your device (Off position), then windows will ask driver for your device, and automatically detected (because drive had been installed already).
Step 7. Your Device will run Format automatically, wait till finish.