iPhone Devs team released a new beta version of their jailbreaking software Redsn0w 0.9.13dev4 to bring tethered jailbreak for iOS 6 GM Build. Due to some unsolved issues with Cydia and basic modules this beta 4 version of Redsn0w would not install Cydia. Redsn0w 0.9.13dev4 supports these A4 iDevices; iPod touch 4G, iPhone 3GS, iPhone 4(GSM) and iPhone 4(CDMA).
iPhone Devs team has provided this information on thier blog:
THIS JAILBREAK IS INTENDED ONLY FOR DEVELOPERS OF JAILBROKEN APPS! There are just too many broken components (Apple’s official apps, 3rd-party App Store apps, Cydia apps, etc) for this to be useful to anyone but those truly looking to fix bugs in their iOS 6 jailbroken apps.
CYDIA WILL NOT BE INSTALLED because it just hasn’t had time to be updated to the new SDK. The only access you’ll get to the device is through SSH or afc2. If you don’t know what either of those are, you shouldn’t be using this developer version of redsn0w!
THIS REDSN0W WILL NOT HACTIVATE! You need to be an iOS developer with a registered UDID to get past the activation screens. PLEASE DON’T PIRATE APPLE SOFTWARE! Only registered devs with Macs can develop iOS applications,and only those people will have legitimate access to the beta IPSWs.
THIS IS A TETHERED JAILBREAK ONLY! No new exploits are being exposed with this jailbreak (it uses geohot’s limera1n bootrom exploit), but that comes at a cost. You will need to use redsn0w to “Just boot” button to be able to use many things, including Cydia and Safari. If you see a white icon for Cydia, or if Cydia or Safari crash when you open them, it’s because you didn’t boot tethered.
They’ve also given the following warning to unlockers:
UNLOCKERS AND THOSE PRESERVING THEIR UNLOCKABLE BASEBANDS SHOULD STAY FAR AWAY FROM THIS! You will very likely lose your unlockable baseband if you try to install iOS 6.
This tethered jailbreak is only meant for developers to test their jailbreak apps with iOS 6.0 firmware. Users can download Redsn0w 0.9.13dev4 for Mac or Windows from the below posted links.