If the device has been modified or rooted, official OTA updates will fail. You must flash the original factory image. Conclusion
Sunmi typically does not provide public "direct download" links for firmware files (.zip or .img) to end-users to prevent accidental damage. To get the correct firmware for your specific region and hardware revision: sunmi v2 pro firmware download upd
Regularly updating your Sunmi OS (based on Android) is crucial for several reasons: If the device has been modified or rooted,
The update will not start if the battery is below 30%. Plug it into a charger. sunmi v2 pro firmware download upd
Sunmi V2 Pro Firmware Download & Update Guide: Keep Your Terminal Running Smoothly