hello i have a b315s-607 locked to zamtel zambia it asks for unlock code . couldnt get it to usb green mode so i followed a tutorial for debranding using bootshot method and flashed polkomtel firmware hoping it will get in usb green mode but still nothing what do i need to do tried multi upgrade tool method it doest turn blue light hen i click start just red light . been trying for days your help will be highly be appreciated.