Direct Download iPhone Firmware Links (All Versions)
Below are lists of direct download links for the iPhone Firmware.
Download the IPSW file without iTunes is better than downloading using iTunes.
NOTE: You must keep that the extension of file is .ipsw
click Tools OR Press ALT + T on keyboard &rarr click Folder options → click View tab → Make sure that “Hide extensions for known file types” option is unchecked.
If you use Safari, you must disable the auto unzip feature.
To install the IPSW firmware file that you have downloaded, read this post: How-to Restore using Shift + Restore method
To download direct IPSW firmware file, click here to find IPSW download links that suitable with your device.
Every time apple release a new iOS, the download links of IPSW firmware file for your device will be available here.