If you are unable to use the previous steps, you will need to use Recovery Mode. Connect your phone to a computer running iTunes. Restart your phone using a method below: iPhone models without a HOME button: Pr
Most of the time it is indeed better to perform updates when using wi-fi networks, due to the size of the file or even for the higher stability if compared to amobile data connection. So,make sure your mobile has the latest versionof its software to ensure it is working at peak perfor...