Is there a way to update/restore my iPhone with a selected version of iPhone firmware?
For a variety of reasons, should you need to restore your iPhone, you may not always want to use the most recent version of the iPhone firmware. We've found a good deal of instruction out there that suggests complicated (and likely ineffective) ways of doing this which usually involve disconnecting your PC from the internet during the early stages of the restore process.
Thankfully, there's a much easier, and effective way to restore your iPhone with a particular firmware version of your choosing
Hold the SHIFT key while clicking the "Update" or "Restore" button in the iPhone tab in iTunes
Hold the option key while clicking the "Update" or "Restore" button in the iPhone tab in iTunes
Subsequently, a dialog box will come up which will allow you to select the firmware file to use for your update. At this point, simply browse to and select the firmware file that corresponds to the version you'd like to restore your iPhone with.
Firmware files have an .ipsw extension and can be found at the following locations:
Documents and Settings\<User>\Application Data\Apple Computer\iTunes\iPhone Software Updates
~/Library/iTunes/iPhone Software Updates