Jailbreak iPad 4.2 or 4.2.1 with Redsn0w 0.9.7b3 (untethered) – MAC GUIDES

For those who want to untethered jailbreak the iPad with iOS 4.2.1, a first beta version of Redsn0w capable of doing so has arrived from the Dev Team. Here's how to proceed.

First of all, I remind you that this is a beta version, i.e. not definitive and could still present many problems (see below). I also remind you that jailbreaking voids the warranty and I advise you to first take a look at our page on iPad jailbreaking, where you will find all the useful information.

The first part of the procedure is the same as that of the tethered jailbreak (read here for the difference between tethered and untethered jailbreak) and works with iPhone, iPod Touch and iPad with iOS 4.2.1 installed. Furthermore, to proceed you must have the SHSH certificates saved for the 4.2 Beta 3 firmware and the 4.2 Beta 3 firmware saved on your computer.

RedSn0w can be downloaded from this page and works, for now, only with Mac OS.
Guide

Perform the tetethered jailbreak normally if you have not already done so with this guide.
In Cydia check that the SHSH: 4.2b3 entry is there. This will be used to see if you have saved the SHSH of Beta 3 of iOS 4.2. Otherwise you will not be able to continue.

Connect your iPad, iPhone or iPod Touch to your Mac
Download this software, extract it. Then open the terminal and type the following text strings in the python-client folder (cd /users/username/Downloads/usbmuxd-1.0.6/python-client if saved in the download folder)
chmod x tcprelay.py
./tcprelay.py -t 22:2222

Open RedSn0w and choose the original 4.2.1 firmware that you also use on your device
Click on Next, select Jailbreak Monte and choose the fw 4.2 beta 3 that you saved on your Mac
Check that the iPad is turned off and connected to the Mac. Press Next again
Put your device in DFU by following the instructions that appear on the screen

Let the automatic procedure continue

Known issues

This jailbreak is not compatible with Ultrasn0w
Being a beta, the procedure will not always be successful
There are some issues with bluetooth not working properly after jailbreak
SpringBoard may crash when accessing the multitasking bar

For this reason my advice is to wait for the final version of RedSn0w to perform the jailbreak with complete peace of mind.
Update 12.27.10
At the moment version 0.9.7b3 seems to have solved most of the known problems, but the advice remains to wait.