1. Ensure your phone is connected to a network with a good signal. An unstable network may cause the downloaded upgrade package to be damaged or incomplete.
2. Ensure your phone has enough storage space to complete the download.
3. Ensure that your phone's battery is no less than 40%; otherwise the system will not allow OTA upgrade. Please perform the upgrade after charging.
4. Avoid using your phone during OTA upgrade. If you do use your phone and interrupt the upgrade, restart it.
If the problem persists, please contact our Customer Support for further assistance.