This Guide applies to iPhone 2G, 3G, 3GS with OS 3.1.3 and Sn0wbreeze version 1.3, 1.4, 1.5.1 and 1.5.2 (the steps are the same).

Sn0wbreeze 3.1.3 v1.3-v1.4-v1.5 has been released which can jailbreak iPhone 2G, 3G and iPhone 3GS on the latest iPhone 3.1.3 firmware.

One thing which is to be noted here is that it will work with iPhone 3GS only if it has the older bootrom (non-MC model).

iPhone 3GS users who have upgraded to the stock 3.1.3 are still out of luck.

Follow the simple step by step guide below to jailbreak your iPhone 2G, 3G and iPhone 3GS (old bootrom only) on iPhone firmware 3.1.3 using Sn0wbreeze. This version of Sn0wbreeze is for iPhones only. iPod touch 1G/2G (older non-MC models) can use redsn0w to jailbreak on 3.1.3 firmware. iPod touch 3G is currently not supported.

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 and the original iPhone OS 3.1.3 for your version of iPhone. Move all these files to your desktop.

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

Step 5: Sn0wbreeze will now ask you to browse for your .ipsw file. Select the correct 3.1.3 firmware .ipsw file by clicking the “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 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 3.1.3 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 downloaded custom firmware 3.1.3. 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 firmware 3.1.3 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 firmware 3.1.3.

How to: Unlock iPhone 3G/3GS on 3.1.3:
You can now follow the tutorial/guide posted here to unlock your iPhone 3G and 3GS (old bootrom only) on firmware 3.1.3 using ultrasn0w or blacksn0w respectively.

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 firmware version 3.1.3 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.

Note for iPhone 3G and 3GS Users (New Bootroms): We strongly suggest that you stay away from this official upgrade until and unless the DevTeam or George Hotz releases new jailbreaking and unlocking tools for 3.1.3 firmware. We will let you know when it will happen. In the meantime you can follow our complete jailbreaking and unlocking guide for iPhone 3.1.2 firmware using blackra1n, PwnageTool, redsn0w, sn0wbreeze, ultrasn0w and blacksn0w.

UPDATE 1: Sn0wbreeze 3.1.3 V1.4 is now LIVE for iPhone 2G, 3G, 3GS and iPod touch 1G. More info and download links can be found here.

UPDATE 2: Sn0wbreeze 3.1.3 V1.5.1 is now LIVE for iPhone 2G, 3G, 3GS and iPod touch 1G, 2G. More info and download links can be found here.

P.S. I haven’t tried this method on my iPhone 3GS yet. I will personally wait for other success stories before I give mine a try. ONLY TRY IT AT YOUR OWN RISK.

Disclaimer: This guide is for testing & educational purposes only. Follow it on your own risk. I’m not responsible for any loss of important data or malfunctioning of your iPhone.