Trouble updating iphone 4
(Access the Library folder in your user folder by holding down the Option/Alt key in Finder and selecting Go Library.) Your Mac may have deleted this file, however.If so, launch your web browser and search for download ipsw.You'll find a number of sites offering links to the file you need.Make sure you get the right one for the device you use.
Alternatively, you can update i OS via i Tunes and save yourself the trouble.
Beware though that at some point Apple will stop "signing" older versions of i OS so it will become impossible to downgrade.
If you have a copy on your hard drive you will find it by following this path: Library/i Tunes and then select the Software Updates folder for your device.
Android alone is more popular than the popular desktop operating system Windows, and in general smartphone use (even without tablets) outnumber desktop use (desktop use, web use, overall is down to 44.9% in the first quarter of 2017).
Mobile devices with mobile communications abilities (e.g., smartphones) contain two mobile operating systems – the main user-facing software platform is supplemented by a second low-level proprietary real-time operating system which operates the radio and other hardware.