If the tool does not recognize your device, try switching to a different USB port (preferably a USB 2.0 port) or replacing the cable. If you encounter an "Unauthorized" error in the MSM tool, you may need a specific version of the tool that includes an "Enable" button or use a bypass tool compatible with Oppo’s older security verification.
: Disconnect the USB cable and power on the phone. The first boot may take several minutes. Troubleshooting oppo a57 cph1701ex-11-a.35 flash file