There is a problem with the permissions of the Mobile Application folder. The baseband does not get updated using this method.
As one forum poster stated on our sister site, “The update downloaded and installed and I got to the 'hello' screen, slided and then the next screen which says 'slide to upgrade' doesn't react and slide, it's just stuck there, frozen!
” Some have tried restoring to factory settings, others have tried a hard reboot, the general consensus on Twitter was that the best option to fix it was to completely wipe the phone and restore it to a new i Phone - proof that it’s important to do a back up before updating.
Generally speaking, restarting your i Phone will solve the freezing issue and complete the i OS 10/9/8 update.
There's also an effective way to reboot your i Phone with Rei Boot, a third-party tool totally for free, especially when your i Phone Home/Volume Down or Power button is broken. First connect your i Phone to PC and launch the free i Phone reboot tool.
Rei Boot and Rei Boot (Mac) enables you to fix i OS freeze, i Phone crashed during i OS 10/9 update, Recovery Mode stuck, DFU stuck, red i Tunes logo stuck, etc. Then Rei Boot will automatically detect the condition of your i Phone.