Power Off your Mobile
Download and extract spflash tool latest version
Now open sp flash tool and chose scatter file
Now press download button.
when Green bar of Ok appears your flashing done.
Now unplug cable
Now insert battery and press power button.
Your flashing is complete enjoy.
if you faced any error copy and paste that error in comments
Oppo i8_Pro Flash File / firmware MT6580 6.1 Without Password