Ensure the MediaTek DA USB VCOM drivers are installed on your Windows PC.
installed. Without these, the software won't "see" the phone when it is powered off. Power off the device. Mt6771 Imei Repair
Flashing a wrong firmware version or a broken ROM. Ensure the MediaTek DA USB VCOM drivers are
Power off the phone, hold both volume buttons, and connect the USB cable. hold both volume buttons