How to Install iPhone Firmware 1.1.2 on iTunes
Apple made their iPhone firmware update available to the public before making it available via iTunes. The file itself weighs in at 160MB and can be downloaded here: iPhone Firmware 1.1.2
The only problem has been the lack of information on how to install the giant file. Although many people have linked to the file, a lot people have struggled to figure out how to install it. Fortunately, it’s an easy process.
Step 1: In iTunes, on the iPhone screen, Option+Click the Restore button (for Windows users it’s Shift+Click).
That’s it! Just one step, then follow the instructions.