Downloading iOS Firmware
If you need to downgrade, update, or restore your iDevice without updating, a great place to download firmware is here. Make sure that “hide unknown file type extensions” is unchecked under folder options in Control Panel, if you are downloading with Internet Explorer, then change the .zip extension to .ipsw
If you are downloading from other browsers such as Mozilla FireFox and Google Chrome, the extension is already set as .ipsw, so there is no need to make any changes.
To use these firmwares in iTunes, simply shift-click restore and select the firmware.
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