How to Jailbreak iPhone 3GS Version 3.1.2

Jailbreaking is a process that allows iPhone and iPod Touch users to run unofficial code on their devices bypassing Apple's official distribution mechanism, the App Store. Once jailbroken, iPhone users are able to download many applications previously unavailable through the App Store via unofficial installers such as Cydia, Rock App, Icy, and Installer.

Jailbreaking, while not illegal, gives a user the ability to install cracked and pirated apps, which is illegal. Jailbreaking, according to Apple, voids Apple's warranty on the device, although this is quickly remedied by restoring the device in iTunes.

So now, the first question is, what do I need to do?

Equipment: iPhone 3GS Version 3.1.2 (7D11)
Jailbreak: blackra1n
PC OS: Windows XP

1. Verify your iPhone version : To verify your software version, simply select "settings -> General -> About" from the main menu. you will see the version number in the list.
2. Download blackra1n and select the correct platform.
3. Plug your iPhone to your computer and make sure iTunes is closed. Run BlackRa1n RC3 and click on “make it ra1n”.

   

4. BlackRa1n will run on your iPhone and it will reboot when done.

   

5. After your iPhone has rebooted, you will notice a new BlackRa1n icon on your springboard.

   

Viola! Your iPhone is now jailbroken, but with only blackra1n, you will not be able to install cracked apps on iPhone version 3.1.2. Stay tuned for upcoming article on how to install cracked apps.

PS: BlackRa1n only supports a tethered jailbreak. This means that once jailbroken you should not let your battery die, reboot or off your phone. If it does die you will need to reconnect it to the computer and double-click on BlackRa1n to boot it up. A hassle I know, but you will not lose any data on your phone.

References:
http://en.wikipedia.org/wiki/Jailbreak_%28iPhone_OS%29
http://www.iphonedownloadblog.com