Download the latest version of iTunes and update your iPhone to the latest 3.1.3 Firmware if you haven’t already done it.
Download redsn0w 0.9.3 for Windows or Mac based on your OS and also download iPhone OS 3.1.2 IPSW file(Yes we need a 3.1.2 firmware also!).
Now run redsn0w and browse to the original iPhone OS 3.1.2 .ipsw file(Be Clear, it is iPhone 3.1.2 IPSW and not 3.1.3). Redsn0w will check if the firmware is valid and will then patch it.
As we are using a iPhone 2G, we need to select “Install Cydia” and “Unlock” to unlock your iPhone 2G.
If you are interested in customizing your iPhone you can choose any/all of the “Custom boot logo”, “Verbose boot” and “Custom recovery logo”, else you can skip this step.
Now redsn0w will show you some instructions to enter into DFU mode.
Hold down the “Power” button and immediately without releasing the power button, also hold down the “Home” button. Without releasing the “Home” button, release the “Power” button but keep holding the “Home” button for 30 seconds.
Your iPhone will reboot once it is jailbroken
Once you are done with jailbreaking your iPhone 2G on 3.1.3 firmware you can unlock it by using BootNeuter app from Cydia.
We are warning you again that this 3.1.3 Firmware jailbreak is strictly for iPhone 2G old models. If you have got an iPhone 3GS/3G or iPod Touch 3G/2G newer model do not attempt to upgrade your firmware to 3.1.3.
