By lex and ParrotGeek.
The first and only method for offline updates/restoring of all original iPhone and iPod Touch IPSW files. In iTunes version 7.6 Apple added a server side online check before each and every restore. This meant Apple decided if a restoe was gonna happen or not. Patched iTunes version 7.5 is a modifed vesion of the iTunes that enables you to restore/update firmware 1.1-iPhone OS 3.1.3 offline without this check completely offline.
This method was first created by Electimon, expanded by ParrotGeek, and finalized by myself into a working method to defeat Apple's control over your device.
32 bit MD5: a136b34263222d0afd4a2400c492507a
64 bit MD5: 5d673a61a5d09e6b08aa7225b1829e4e
Uninstall any current iTunes version on your Mac using iTunes Eraser. Download it, and run the script. Then reboot your Mac.
Install an iTunes version between 7.6-9.2.1. iTunes 7.7.1 supports firmware 1.1-iPhone OS 2.2.1. iTunes 9.2.1 supports firmware 1.1-iPhone OS 3.1.3. Some jailbreaks/hacking programs require specific iTunes versions to be installed, keep these things in mind when choosing which iTunes you need for your purpose. Once you have decided, download and run the iTunes installer for that version, you can download those from the iTunes page.
Download and extract the Patched iTunes version 7.5, which is availble from above. All you need to do now is run the patched-itunes-7.5.app file. iTunes will open. Next connect your iPhone or iPod Touch to the Mac with a USB Dock cable, and enter it into DFU Mode manually to prepare for the restore. To do so:
You'll know if it worked if the screen of the iPhone or iPod Touch is black, but not off. The iPhone or iPod Touch will now appear in iTunes. Click ok when prompted by iTunes that your iPhone or iPod Touch is in DFU mode. Then place the mouse cursor on the restore button. Press down the the option key and click. A new window will open, select your desired IPSW file, and wait for the restore to complete.
After the restore, if your iPhone is in Recovery Mode on 1.1-2.0 beta 3 firmware you can use ZiPhone to boot it to the Activation screen. If your iPhone refuses to boot, restore it again using the same IPSW file and try to boot it again. Although ZiPhone can activate firmware 1.0-2.0 beta 3, you'll need to use another utility for firmware 2.0 beta 4-iPhone OS 3.1.3 to activate it. Some useful utilities for this are on the Jailbreaks page. If you have an iPod Touch, simply quit the Patched iTunes v7.5 app and open the original installed iTunes to bypass the connect to iTunes screen.
If your restore gets stuck on "Waiting for iPod" or "Waiting for iPhone" for a few minutes and never continues, this means your iPhone or iPod Touch model is incompatibile with the firmware you are trying to restore to, because of NAND flash differences used in newer models. You can't restore these firmwares with iTunes but you can dual boot them via UiBoot.
If you get iTunes error 1600, quit the Patched iTunes v7.5 app and open it again. This time it should work. If the restore starts, runs for awhile, and then does not complete successfully then the original iTunes version you installed after using iTunes Eraser does not support restoring the firmware you selected.
The Windows method is slightly different, due to the fact that simple hex editing iTunes.exe does not in itself allow it to function along side a newer version. Not sure exactly how this isn't working, but there is still a way.
Install iTunes version 7.5 as normal.
Unzip the iTunes 9.2.1 mobile device msi from the download above. Double click it, and wait for the installer to complete. Reboot your computer for good measure, and you'll be able to restore firmware 1.1-iPhone OS 3.1.3 offline on the original iPhone and iPod Touch.
Unfortunately, you'll have to update your iTunes past 7.5 to sync/interact with the iPhone or iPod Touch on 2.0 b4-3.1.3. To restore you'll have to start over. At least it's possible.