Just a quick heads-up: The iPhone DevTeam dropped a new redsn0w update which comes with support for iOS5b4. In conjunction with iOS5 beta4 being released to iOS developers, redsn0w 0.9.8b4 is now available for jailbreak app developers. Remember, it’s a tethered jailbreak right now so you’ll need to use redsn0w to boot into a jailbroken state at each power cycle.
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 5.
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, MobileSubstrate apps, etc) for this to be useful to anyone but those truly looking to fix bugs in their iOS 5 jailbroken apps. (Seriously!)
THIS REDSN0W WILL NOT HACTIVATE! You need to be an iOS developer with a registered UDID to get past all the new activation screens. PLEASE DON’T PIRATE APPLE SOFTWARE! 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 tethered now” 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.
IF YOU HAVE THE 06.15 BASEBAND ON YOUR 3GS…this redsn0w will get you past the iTunes restore error you’ll get when using the stock IPSW (nobody other than those with the 06.15 baseband should be going anywhere near the stock IPSW!).