2.0.2 Update :)

Unfortunately Sn0wbreeze 2.0.1 has few bugs causing iTunes to throw an error 17/40 while using hactivate iPhone options of Sn0wbreeze 2.0.1. A quick fix for hacktivation issue was to uncheck the Activate Phone option in Expert mode and recheck it.

But if you haven’t jailbreaked iOS 4.1 yet then Sn0wbreeze 2.0.2 is the way to go. Download Sn0wbreeze 2.0.2 and follow jailbreak guides below.

Updated guide

Step 1: Download and install the latest version of iTunes.

Step 2: Now start iTunes and sync your iPhone with your PC so that it backs-up all your important data including settings, apps, music, contacts and photos.

Step 3: Download Sn0wbreeze 2.0 and the original iOS 4.1 firmware file. Move all these to your desktop.

Step 4: Start Sn0wbreeze and select “Simple Mode” for easy process.

Step 5: Sn0wbreeze will ask you to locate the .ipsw original firmware file. Point to the correct iOS 4.1 file by clicking on “Browse” button. Sn0wbreeze will verify the selected file and then will present you with following screen.

Step 6: Click on “Yes” when Sn0wbreeze asks you “Do you want to activate your iPhone?” for hacktivation. Click on “No” only if you are on an officially supported carrier like AT&T.

Step 7: Sn0wbreeze will now create custom firmwares for your iPhone which is jailbroken, (Save it on your desktop)

Step 8: Now Download iReb V4.0 and make sure that iTunes is launched

Step 9: (This step for iPhone 3G, and iPod touch 2G [MB] only) Launch iReb (to bypass iTunes errors) and choose “Online Mode” then choose your device

Put your iPhone in DFU mode by following this step:

Turn iPhone off.
Hold Power and Home buttons together for 10 seconds or so.
Release Power button but keep holding the Home button until your computer recognizes a new USB device.
iTunes will now recognize your iPhone

Step 10: Now, You will have to restore your iPhone to the jailbroken custom firmware by Clicking on the iPhone icon on the left sidebar of iTunes then hold left “alt” button (“Shift” button on Windows) on the keyboard and then click on “Restore” then release the alt button, Now Select the custom firmware created by Sn0wbreeze and Let iTunes finish the restore. Once you are done you will be jailbroken on 4.1!

via iPhoneblogr

Old Guide

Update 1 : Sn0wbreeze 2.0.1 just released to deal with error 37 that people have been running into with the iPhone 3G. You can download sn0wbreeze 2.0.1 here.

Sn0wbreeze 2.0 was released earlier today. It brings all kinda new jailbreak love back 4.1 firmware. Check out the step by step guide below on how to jailbreak your iPod or iPhone on the 4.1 firmware. Meanwhile remember to stay away from any greenpois0n jailbreaks out, as they are viruses dressed as jailbreaking tools. Read more on thathere.

Read all directions step by step before asking questions:

And again Redmond Pie delivers on a quick tutorial on how to jailbreak your device on 4.1. It brings support for a bunch of devices running on iOS 4.1. These include:

iPod touch 1G
iPod Touch 2G (Non-MC Model)
iPod touch 2G (MC Model, must be previously jailbroken on 3.1.2)
iPod touch 3G (Must be previously jailbroken on 3.1.2)
iPhone 2G
iPhone 3G
iPhone 3GS new bootrom (Must be previously jailbroken on 3.1.2)
iPhone 3GS old bootrom (Must be already jailbroken. If you are jailbroken using Spirit or JailbreakMe, install Spirit2Pwn from http://repo.woowiz.net.

Like PwnageTool for Mac, you can use Sn0wbreeze 2.0 on Windows to build custom firmware files without upgrading the baseband.

Except for iPod touch 4G, Sn0wbreeze supports all previous generation of iPod touches, including iPod touch 3G and iPod touch 2G (MC Model). If your iPod touch meets the criteria listed above, then you can jailbreak it on iOS 4.1 using Sn0wbreeze 2.0.

Simply follow the instructions posted here(ignoring most of Step 6 as it is for iPhone only) to jailbreak your iPod touch 3G and iPod touch 2G (MC and Non-MC Model) on iOS 4.1.

Sn0wbreeze 2.0 is out! Just like PwnageTool for Mac, you can now cook custom firmwares of iOS 4.1 on Windows without upgrading the baseband, which ultimately means that you can use ultrasn0w unlock software to unlock your phone on the older baseband.

Sn0wbreeze 2.0 supports following devices:

iPod touch 1G
iPod touch 2G (Non-MC Model)
iPod touch 2G (MC Model, must be iOS 3.1.2. Does not need to be jailbroken on 3.1.2)
iPod touch 3G (Must be previously jailbroken on 3.1.2)
iPhone 2G
iPhone 3G
iPhone 3GS new bootrom (Must be previously jailbroken on 3.1.2)
iPhone 3GS old bootrom (Must be already jailbroken. If you are jailbroken using Spirit or JailbreakMe, install Spirit2Pwn from http://repo.woowiz.net.

NOTE: Sn0wbreeze 2.0 WILL NOT jailbreak iPhone 4, iPad and iPod touch 4G.

Instructions are as follows:

Step 1: Download and install the latest version of iTunes.

Step 2: Now start iTunes and sync your iPhone with your PC so that it backs-up all your important data including settings, apps, music, contacts and photos.

Step 3: Download Sn0wbreeze 2.0 and the original iOS 4.1 firmware file for your version of iPhone or iPod touch (download links given below). Move all these files to your desktop.

Step 4: Start Sn0wbreeze and select “Expert Mode”.

Step 5: Sn0wbreeze will now ask you to browse for your .ipsw file. Select the correct iOS 4.1 firmware .ipsw file by clicking the “Browse” button. Sn0wbreeze will verify the selected file and then will present you with following screens.

Step 6: Now if you are on iPhone 3GS (New Bootrom) or iPod Touch 3G, make sure you hit “General”-> and check “Use iBooty Method (3.1.2 Required!).

Also check “Activate The iPhone” if you are on unofficial carrier and want Sn0wbreeze to hacktivate your phone.

Step 7: Now simply select “Build IPSW”. Sn0wbreeze will now create the custom .ipsw file for your iPhone which will be jailbroken.

Step 8: Now you will have to restore your iPhone to this custom firmware 4.1 that you just cooked using Sn0wbreeze for your iPhone. Click on your phone from the sidebar in iTunes and then press and hold left “Shift” button on the keyboard and then click on “Restore” (Not “Update” or “Check for Update”) button in the iTunes and then release the “Shift” button.

This will make iTunes prompt you to select the location for your custom firmware 4.1. Select that custom .ipsw file and click on “Open”.

Step 9: Now sit back and enjoy as iTunes does the rest for you. This will involve a series of automated steps. Be patient at this stage and don’t do anything silly. Just wait while iTunes installs the new iOS 4.1 on your iPhone. Your iPhone Screen at this point will be showing a progress bar indicating installation progress. After the installation is done, iPhone will restart automatically and you should now have a fully jailbroken iPhone running on iOS 4.1.

How to: Unlock iOS 4.1 (Old Baseband): Once you are done with the jailbreak, you can follow our step by step guide posted here to unlock your iPhone on iOS 4.x, on older baseband using Ultrasn0w.

Step 10: Once you are done with the unlocking and jailbreak process. You can now restore all your settings, apps, music, contacts and photos to the newly installed iOS 4.1 by restoring the backup that you made in Step 2 from iTunes.

Feel free to ask me any question here should you run into any problem during the jailbreak process.

Download iTunes 10 for Windows
Download iOS 4.1 for iPod touch 2G/3G
Download iOS 3.1.3 for iPod touch 1G
Download .NET Framework 3.5 (required to run Sn0wbreeze)
Download Sn0wbreeze 2.0 (Windows Only)

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