1. The mobile phone is not connected to the network.

2. Connect to the network, but the network signal is too poor and unstable. You need to connect to a stable and better network. It is recommended to update with wifi.

3. If there is something wrong with the system, you can go to the exclusive store for inspection and maintenance.

4. You can use itune on your computer, and then download the firmware to update it manually.

Extended data

IOS is a mobile operating system developed by Apple. Apple announced this system for the first time at Macworld conference on June 9, 2007. Originally designed for iPhone, it was later applied to iPod touch, iPad, Apple TV and other products. IOS, like apple's Mac OS X operating system, belongs to a commercial operating system similar to Unix. Originally this system was called iPhone OS. Because iPad, iPhone and iPod touch all use iPhone OS, it was announced at the 20 10WWDC conference that it was renamed as iOS(iOS is the registered trademark of Cisco's network equipment operating system in the United States, and Apple's renaming has been authorized by Cisco).

Reference: Baidu Encyclopedia: iOS