If your mobile phone is root, it is recommended that you download the firmware package on the official website to restore the system. You can download the firmware package on the official website to restore the mobile phone system. This is the link:https://www.vivo.com/upgrade/detail?modelId=9&type=2 After downloading, do not unzip it. Copy and paste it directly into the root directory of mobile phone storage. Follow the following tutorial http://bbs.vivo.com.cn/forum.php?mod=viewthread&tid=1960622 (Source: vivo smartphone fan V community) Before the firmware upgrade, it is recommended that you back up the phone data to prevent data loss.