Along with Redsn0w, iPhone Dev Team has also released the PwnageTool 5.1.1 to support iOS 5.1.1 untethered jailbreak for all earlier devices. The updates version of PwnageTool also includes the rocky raccoon untether package released by pod2g and dream team.
Users who rely on ultrasn0w unlock can use pwnagetool to cook custom firmware to preserve the baseband from updated and then jailbreak untethered their device. All A4 devices including iPhone 4, iPhone 3GS, iPad 1, and iPod touch 3G, 4G and Apple TV 2 can download and use PwnageTool 5.1.1 from the link below.
From the iPhone Dev Blog,
PwnageTool also avoids any possible sync issues, but again it applies only to A4+earlier devices. If you unlock your iPhone with ultrasn0w or a commercial method, you must use PwnageTool to avoid updating your baseband otherwise you’ll lose the unlock. PwnageTool will also jailbreak+untether the AppleTV2,1 5.0_2B206f (unless you customize the IPSW further, you’ll have just basic SSH access to the device).
Alternatively, you can use Absinthe 2.0 or Redsn0w 0.9.12b1 to untether jailbreak your device. We will soon be posting the guide to use PwnageTool 5.1.1, so stay tuned with us on @Jailbreakwire, and Facebook Fanpage.