Apple has released the new version of firmware for all devices (besides first generations of course), version 4.2, to developers. The final, gold master file is ready. This means it will install even if you’re not a developer. This is the firmware that brings folders and backgrounding to the iPad and printing to all devices! The firmware will probably be out officially from Apple via iTunes within a week or so but if you want it early, follow the directions below. If you want to jailbreak, see the instructions following the update instructions.
As of the writing of this article, Cydia isn’t ready for 4.2 and I’m also not sure that this will work on the iPad for sure. Please correct me on this. The dev team blog says to point redsn0w at firmware 4.1. The iPhone runs 4.1 but not the iPad. You may be able to point it a previous iPad firmware but I haven’t tested this yet. I’m honestly waiting to jailbreak myself once Cydia is ready. We will update this article once we can confirm. I recommend syncing your device before starting this.
Instructions on updating to 4.2
1. Download the newest version of iTunes, 10.1 (links here)
2. Install the new iTunes.
3. Download the correct firmware for your device. (http://gumballtech.com/2010/11/01/ios-4-2-gm-released-for-all-devices-download-here/)
4. In iTunes, select your device and hold the Shift(windows) or Option(Mac) key while clicking the update button. This will open a window to choose your own firmware. Select the one you Just downloaded.
5. Now just wait until the update is complete. You will then have firmware 4.2!
Instructions on Jailbreaking 4.2
1. Download redsn0w from here: http://blog.iphone-dev.org/post/1452044444/redsn0w-limera1n-fun
2. Your device will be on 4.2 but when you run redsn0w you will select firmware 4.1 on your computer. You can download firmware 4.1 for your iPhone here. Just follow the instuctions with redsn0w and you’ll be jailbroken. Remember, Cydia is not yet working on 4.2.