Change the USB port on your PC, preferring USB 2.0 over USB 3.0 ports.
Sometimes the firmware update alone doesn’t unlock the SIM – you may need a : huawei b315s-607 unlock firmware
Search for firmware files labeled:
To flash your device, you typically need these tools often found on sites like 4PDA or GSM-Forum : Change the USB port on your PC, preferring USB 2
Modifying the official software immediately voids any remaining warranty. huawei b315s-607 unlock firmware