Yesterday Apple released the final build of iOS 4.2, more specifically, iOS 4.2.1. The jailbreaks are ready to go, and we can help you get through the process of jailbreaking your device.
But first, a few notes: If you have an unlocked phone, DO NOT use this jailbreak. In fact, if your phone is unlocked you should be avoiding iOS 4.2.1 altogether.
Also, this is a tethered jailbreak. This means you will have to plug your device into your computer anytime you reboot in order to maintain your jailbreak functionality and run RedSn0w. This pertains to some of the newer iOS devices such as the iPhone 3GS (new bootrom) the iPad, the iPod Touch 2G (MC Model), iPod Touch 3G and the iPod Touch 4G as well as the iPad. Meanwhile, older devices like the iPhone 3G and the iPod Touch 2G (Non-MC model) can use an untethered jailbreak.
That said, let’s get started.
1) Grab the jailbreak from one of the following RedSn0w download locations:
Mac – Redsn0w_mac_0.9.6b4.zip
Windows – Redsn0w_win_0.9.6b4.zip
2) Run Redsn0w, and direct it to your current ipsw.
The files can be found at the following locations. We suggest creating a new folder with a convenient name like “Jailbreaks” with a copy of the ipsw.
– Mac OS XiPhone ~/Library/iTunes/iPhone Software UpdatesiPad ~/Library/iTunes/iPad Software UpdatesiPod touch ~/Library/iTunes/iPod Software Updates
Note: The tilde “~” represents your Home directory.
– Windows XPiPhone C:\Documents and Settings\[username]\Application Data\Apple Computer\iTunes\iPhone Software UpdatesiPad C:\Documents and Settings\[username]\Application Data\Apple Computer\iTunes\iPad Software UpdatesiPod touch C:\Documents and Settings\[username]\Application Data\Apple Computer\iTunes\iPod Software Updates
Note:If you don’t see the Application Data folder, you may need to show hidden files.
– Windows 7 and VistaiPhone C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPhone Software UpdatesiPad C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPad Software UpdatesiPod touch C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPod Software Updates
Note: If you don’t see the AppData folder, you may need to show hidden files.
3) You should see the following message:
4) Select “Install Cydia” and hit next:
5) Make sure your iPhone or iPod Touch is OFF and PLUGGED IN to the computer before you hit next, as shown below:
6) After hitting next, the guide will walk you through putting your device in DFU mode. Follow the onscreen instructions exactly.
7) Sit back and watch that beautiful progress bar:
8) Finally, you will see the following message:
9) If you have one of the newer devices such as the iPhone 3Gs (New Bootrom), iPhone 4, iPod Touch 2G (Non-MC model), 3G, 4G or the iPad, and want to maintain jailbreak functionality and use RedSn0w, you will have to plug in your device and run RedSn0w and check off the “Just boot tethered right now.” Otherwise, your jailbreak Apps will not work.
10) Many users have noted that Cydia does not seem to work when the jailbreak finishes installing. This is because you have to reboot your iPhone or iPod Touch and choose that “Just boot tethered right now” option. When you boot that way, Cydia will work. Know that from now on, you will have to boot that way to have your jailbroken Apps work. Hence the name “Tethered” jailbreak, which literally means your device has to be tethered to your computer each time you turn it on. (Not to be confused with waking your iPhone from being asleep or on standby). Unfortunately, this is the only way to do it right now. Which is why many will hold off for untethered jailbreaks. We hope that clears things up.