The PC should detect a new port, typically labeled as or "Unisoc Diag" in the Device Manager.
Open your preferred service tool (e.g., CM2 or a free IMEI tool). enter diag mode spd
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Try a different USB port (preferably USB 2.0) or a different cable. Some modern USB 3.0/3.1 ports have timing issues with older SPD bootloaders. Conclusion The PC should detect a new port, typically
Enter diag mode SPD? [YES] [NO]