We sincerely apologize for the inconvenience and aim to assist you:
Firmware Upgrade:
A serial number error during self-check may indicate issues with the flight controller or system files. Try re-upgrading both the flight controller and ROV firmware, then restart the device. If the upgrade fails, please provide a screenshot or video recording of the error message for further analysis.
System Card Check:
Corrupted system card files can cause serial number query failures. You may attempt to format the TF card (ensure it is a U3 CLASS10 high-speed card) or replace the card reader component.