The iPhone Dev Team says:
We’ve released redsn0w 0.9.8b6 to jailbreak iOS5 beta6 (point it directly at the beta6 IPSW). Two important notes about this version: (1) Please let your device boot normally to IOS5b6 and do a clean shutdown (slide to power off) before jailbreaking. (2) Boot logos have intentionally been disabled for now, so you’ll see a black screen on tethered boots (you can re-enable logos or verbose boot with command-line options if you really want them back).
Due increased sensitivity to abrupt filesystem shutdowns in IOS5b6, it’s very important that you do a clean shutdown before running redsn0w.
Let us put it in layman terms for you:
Redsn0w 0.9.8b6 will recognize the iOS 5 beta 6 ipsw so you need to point redsn0w directly to the corresponding iOS 5 beta 6 ipsw for your iPhone, iPad or iPod touch. Before you start the jailbreak procedure, make sure that the device has properly booted in to iOS 5 beta 6 and then do a clean shutdown by pressing and holding the Power button until slide to power off appears. Boot logos have been disable and you will no longer see a pineapple when booting iOS 5 beta 6 tethered after the jailbreak. If you want to, you can re-enable boot logos or the verbose boot via command line. Since iOS 5 beta 6 is more sensitive to sudden filesystem shutdowns, it is imperative that you properly shut down your device before jailbreaking it with redsn0w 0.9.8 beta 5.
How to jailbreak iOS 5 beta 6 using redsn0w 0.9.8 b6:
The procedure to jailbreak iOS 5 beta 6 tethered using redsn0w 0.9.8b6 is exactly the same for Windows and Mac. Simply follow the guide posted here. This guide contains all the steps required to be done when jailbreaking and booting iOS 5 beta firmware using redsn0w. Just select the iOS 5 beta 6 ipsw in Step 5.
If you’re wondering why this version of redsn0w is being called the “JetBlue Edition,” let us tell you that there’s nothing new in this version. Its being called this because MuscleNerd did most of the work on redsn0w 0.9.8b6 when he was aboard a JetBlue flight from Boston to Jacksonville.
Download redsn0w 0.9.8b6 for Windows and Mac.