A：System upgrade failures can be troubleshooted as follows:
1. System update cannot detect the new version. Please ensure your mobile network connection is normal. If the system update prompts that you are already using the latest version, you generally do not need to update again. If the version date is too old and cannot be detected, please provide your phone's IMEI, SN, and version number to customer service via email for verification and resolution.
2. System update can detect the new version, but the download fails. Please check the network. Generally, poor mobile network signal or network congestion causes download failure. It is recommended to try downloading again at a different time or with a different network.
3. The new system version is successfully downloaded, but after restarting the phone, it does not enter the upgrade installation interface or the installation fails.
① It may be due to an unstable network causing errors in the downloaded system program. You need to try downloading again at a different time or with a different network.
② If a TF card is inserted, it may cause file read errors. Please remove the TF card and download the system again.
③ After ruling out the above factors, long press Settings - Application Information - Storage and Cache - Clear Storage Space and Cache, and then download again.