[BeerBear]

*NEW: Untehtered method can be found HERE. MAC OSX and Windows for now.

For those of you who don’t know, Redsn0w 0.9.6b4 is based on Geohot’s Limera1n bootrom exploit which has already pwned all current iOS devices for life.

The bad new is that right now, the redsn0w 0.9.6b4 is a tethered or semi-tethered jailbreak for some devices (i.e. you will lose your jailbreak every time you reboot your iDevice, so you have to follow the following steps every reboot to have a jailbroken device).

Untethered Devices:
iPhone 3GS (old bootrom)
iPhone 3
iPod touch 2G (Non-MC Model)

Tethered Devices*:
iPhone 3GS (new bootrom)
iPhone 4
iPad
iPod touch 2G (MC Model)
iPod touch 3G
iPod touch 4G

NOTE: Those of you who rely on a carrier unlock stay away from Redsn0w and iOS 4.2.1.

Files required:
iTunes (at least 10.1): official download

MAC -> redsn0w_mac_0.9.6b4.zip ~11.33 Mb: RS | DF | FF | HF | MU | MF
WIN -> redsn0w_win_0.9.6b4.zip ~10.6 Mb: RS | DF | FF | HF | MU | MF
Also you can try newest versions of redsn0w from here.

Direct download links for iOS 4.2.1 (Official):
iPhone 3G
iPhone 3GS
iPhone 4
iPod touch 2G
iPod touch 3G
iPod touch 4G
iPad 3G and Wi-Fi

Guide: video version: http://www.youtube.com/watch?v=P6RJcxqFdE4

STEP 1: Download redsn0w 0.9.6b4, iOS 4.2.1 for your device.

STEP 2: Update to 4.2.1 firmware using the IPSW file you just downloaded via iTunes 10.1.

STEP 3: Launch Redsn0w 0.9.6b4, and browse for iOS 4.2.1 firmware final version


STEP 4: Select "Install Cydia" and click on "Next"


STEP 5: Now make sure your device is both OFF and PLUGGED IN to the computer before you click “Next”.


STEP 6: At this stage you will need to put your iPhone in DFU mode by holding “Power” button and then while holding the “Power” button, you will now have to hold “Home” button too. Now after few seconds release “Power” button but keep holding “Home” button until installation begins.

STEP 7: You will Get a Jailbroken Device on the latest iOS 4.2.1 as soon as the process ends.

STEP 8: This step is only for these devices iPhone 4, 3GS (New Bootrom), iPod touch 4G, 3G, 2G, iPad. While this is tethered jailbreak and whenever you want to do anything related to jailbreak like SSH your device, or running Cydia, you must first run your device in the so called “jailbroken state” on every reboot by using “Just boot tethered right now” option.

[Hook/\hzorr]

YAY!!! finally can upgrade to 4.2.1 from 4.1.

Thanks for finally confirming that this can be done.

Is this limited by tethered or untethered?

Edit never mind the question, read further and found my answer.

to bad its not working for me... im just stuck after the reboot, saying "waiting for reboot" but nothing happens!

[BeerBear]

What OS do you have? If it's Win7 then try to run redsn0w in Win XP SP3 compatibility mode with administrator rights. Try another USB port or another PC.

[ga!nusha]

Worked perfectly on iPhone 4 and XP

This is way old sorry guys but I've jailbroken all my phones with 0.9.6b5 for quite a few months now I believe since october 2010 and that is also a tethered jailbreak 4.2.1. but now there is untethered jailbreaks from greensn0w and geohotz is also schduled to release his utethered jailbreak for iOS 4.2.1.

[BeerBear]

I wrote that you can try newest versions from dev's page.
And if you know new ways to JB, please share them with us

[ga!nusha]

Hehe, by greensn0w you mean GreenPois0n. It was released earlier today though in our part of the world it was night when it was released. Hold on to your pants, post will be updated soon

LE: d0ne!

what about redsnow MC version ?

[BeerBear]

You need exaclty redsn0w? There is newer JB: viewtopic.php?f=1047&t=161646

Hi im using Iphone 3gs 16gb with jailbreaked and unlocked to 4.1 and now i want to upgrade to 4.2 my baseband version is 06.15.00 ,Is it possible to upgrade or jalbreak by redsnow ? Reply me asap

[BeerBear]

I think better use this: viewtopic.php?f=1047&t=166010