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.
Note that this is a tethered jailbreak. You will have to plug in your iPad every time you boot it to run your jailbreak Apps and RedSn0w.
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 X: /~/Library/iTunes/iPad Software Updates
Note: The tilde "~" represents your Home directory.
– Windows XP: 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 Vista: C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPad 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) Check off Install Cydia as shown below:
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 wait for now.
8) You will get the following message
9) Important – as we mentioned with the iPhone jailbreak, you have to plug in your device every time you turn it on. Launch RedSn0w and choose "Just Boot Tethered right Now." Otherwise, you will not be able to run jailbreak Apps like Cydia. You will just see a little grey box.