A good news for iOS 5 as iPhone Dev Team has updated Redsn0w to 0.9.9b4. The update is has a good effects and improvements for iOS 5 . In this topic we will introduce the updated Redsn0w and how to install it.
Update #12: For those of you who experiment with your own custom ramdisks using the -r command-line option, version 0.9.9b4 adds auto-detection support for iOS5. This is needed because iOS4 and iOS5 treat the root partition differently (it’s encrypted in iOS5). redsn0w will now upload the correct iOS5 kernel by itself, but it’s up to your own launchd to determine if it needs to mount using the old or new partition scheme.
redsn0w now also accepts both native and img3-encapsulated versions of files you provide via the -r, -k, and -d command-line options (do redsn0w -h to show all the available options).
You can use this tutorial we posted before and follow the instructions to install Redsn0w.
This is Tethered jailbreak so you have to connect your device with computer and run Redsn0w again if your device has been shutdown.
If your you rely on unlock, don’t use Redsn0w as it upgrades your baseband which cannot be unlocked so you may use Sn0wbreeze 2.8b8 to jailbreak iOS 5 GM .
Download Redsn0w 0.9.9b4 for Mac
Download Redsn0w 0.9.9b4 for Windows
Update: Now you can make iPhone official factory unlock, you can check the details from here