How To Jailbreak iOS 6 With Official Cydia On iPhone And iPod touch (A4) Using Redsn0w 0.9.15b1

iPhone Dev-Team have just updated Redsn0w, adding full support for final public release of iOS 6 on select devices with official version of Cydia, along with tons of new features which are detailed after the jump.
Redsn0w 0.9.15b1 for both Windows and Mac not only adds support for tethered jailbreak of iOS 6 on A4 based devices, but also for re-restoring and downgrading of select devices from iOS 6 to an older firmware, or in case of re-restoring, from iOS 5.x to iOS 5.x.
Supported devices:
First and foremost, it is important to note this is a tethered jailbreak and is only meant for devices boasting an A4 processor (or below), namely: the iPhone 4, iPhone 3GS and the 4th-gen iPod touch. Devices with A5 (iPhone 4S, iPad 2), A5X (iPad 3) and A6 (iPhone 5) processors are not supported at this point. Hacktivation + baseband preservation support has also been added for iPhone 4 and 3GS.

This latest version of Redsn0w does not require the user to go through the trouble of downloading and pointing the app to the iOS 6 IPSW for the jailbreak (the older version of Redsn0w, as mentioned in our previous jailbreak iOS 6 guide, required manual IPSW selection). Instead, the latest Redsn0w recognizes the firmware already installed on your device, downloads the required files and proceeds with the jailbreak. It’s that simple. Cydia, as mentioned above, is now also included as part of this Redsn0w’s release.

Instructions on how-to jailbreak iOS 6:
1. Redsn0w 0.9.15b1 can be downloaded from here (Windows | Mac).
2. Download iOS 6 from here, and update your A4 powered device to it. (check out this post if you want to read on how to update to iOS 6 the right way. Those of you who rely on unlock please read the note below before proceeding with the update.)
3. Start Redsn0w. Run it in Administrator mode if you are on Windows. OS X Mountain Lion users need to start it by Ctrl-Click on the Redsn0w icon and then selecting Open from the new menu.

4. Click on Jailbreak, select Cydia and enter DFU mode when Redsn0w prompts you to with the help of onscreen instructions. Once the device is in DFU mode, Redsn0w will start jailbreaking the device using limera1n exploit. When done, select “Autoboot this device when it connects in DFU mode” option to enter tethered mode for the time being.
After a short while, the device will reboot with familiar Cydia icon on the home screen.
Note for iPhone 4 and iPhone 3GS Ultrasn0w unlockers: You will first need to preserve your older baseband to be eligible for unlock. Click on “Extras” option and then select “Custom IPSW” option. Select the required iOS 6 IPSW file for your device, and let Redsn0w make the custom firmware for you. Once done, enter Pwned DFU mode by selecting “Pwned DFU” from Redsn0w’s Extras option, and then restore to this custom firmware.