What Does It Mean When Your iPhone Says "Preparing Update?"
Apple regularly releases updates to the iPhone's operating system, which you can then download and install through your phone's wireless connection. After your phone downloads the update files, it displays a message declaring "Preparing Update." As the message suggests, your iPhone is preparing the files necessary to install and configure the new update.
1 Forever Preparing
Although you can see the "Preparing Update" message for some time, it doesn't necessarily mean there's a problem. If, however, you see this message for an excessively long period of time, you may have encountered an error. Various factors will affect the time your phone takes to prepare and complete the update, such as connection issues or a lack of response from Apple's servers, and some users have reported times ranging from 20 minutes to an hour or more. If you suspect an error has occurred, or see no activity from your iPhone after over an hour, cancel the update and try again later. If the error persists, visit your local Apple Store Genius Bar to troubleshoot the issue. (See Resources.)