HOWTO: Untethered iOS 4.2.1 iPhone Jailbreak Instructions (Redsn0w)

The long awaited untethered jailbreak for iOS 4.2.1 is here, albeit in limited fashion. The instructions below pertain to Redsn0w 0.9.7b1, a beta release of the so-called "backup plan" untethered jailbreak. This release is not the final release and, being a beta, requires a bit more effort than the eventual final release should. This jailbreak is also limited to the iPhone 4, iPad and iPod Touch 4G.

The following provides step-by-step instructions on how to jailbreak your iPhone (or other iOS device) using Redsn0w 0.9.7b1.

IMPORTANT: If you require an unlock and not a JAILBREAK ONLY, do not proceed.

  • usbmuxd (which you can download from here)
  • a jailbroken (tethered) iOS 4.2.1 iPhone 4, iPad, or iPod Touch 4G. Full instructions for completing the tethered iOS 4.2.1 can be found here
  • the official iOS 4.2b3 firmware file
  • your SHSH blobs from 4.2b3 saved w/ Cydia (locally saved files aren't supported yet)

Step 1

Get usbmuxd unarchived, and up and running. Pick a directory to unarchive it to then, using Terminal, navigate to the python-client subdirectory and start usbmuxd as shown below. Technically, it isn't necessary to start usbmuxd just yet, but there's no reason not to start it and get it out of the way right off the bat.
ios iphone ipad untethered jailbreak instructions

If you're having trouble reading the commands in the image, that's

- chmod +x (makes it executable)
- ./ -t 22:2222

Step 2

Connect your iPhone 4, iPad or iPod Touch 4G and launch Redsn0w.

ios iphone ipad untethered jailbreak instructions

Redsn0w will immediately request that you browse to and select your official iOS 4.2.1 firmware file. Navigate to, select the file, and click "Next".

ios iphone ipad untethered jailbreak instructions

Redsn0w will process the firmware file and inform you when it is ready to proceed.

ios iphone ipad untethered jailbreak instructions

Step 3

Select the "Jailbreak Monte" option. You can uncheck "Install Cydia" as you're required to begin these instructions with a jailbroken iOS 4.2.1 device running Cydia. Redsn0w will again prompt you to point it to an iOS firmware file, this time for iOS 4.2b3.

ios iphone ipad untethered jailbreak instructions

Step 4

Make sure your iPhone, iPad or iPod Touch 4G is OFF and click "Next". Then follow Redsn0w's instructions on how to put your device into DFU mode and sit back and let the process complete.


I have read that the later model iphone 3Gs and the Ipad have identical hardware, will this untethered jailbreak work? I have to forcefully upgrade because all the newest app required iOS 4

Out of curiosity... I got a brand new virgin iphone4 under 4.2.1 ver sion firmware can this Redsn0w jailbreak it?


Same here...brand new iPod touch 4G v4.2.1 -- Is it safe to try this Jailbreak and can I revert back to factory settings if required?....thanx

No you can't. Look at the requirements, you need 4.2b3 shsh blobs.

yes it can, my friend did it for me

Can this be done on a windows machine at all?

Nope. This is still a beta version of the jailbreak and it only applies to MAC. The full version of jailbreak will be out soon.

Hey i am having trouble i have the newer model of the iphone 3gs and i have a tethered jailbreak on it with redsn0w ,, my shsh blobs are saved 4.2.1 and 4.2b3 only on tinyumbrella but does not show it on cydia, also when i go to pick the official firmware on the redsn0w it doesnt let me check the jailbreak monte option because there is none