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3.1 betas are not yet jailbeakable.
 
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3.1 betas are not yet jailbeakable.

I think he meant the new update that came out last week?
 
yes you can do it for 3.0.1, but not for 3.1 beta

http://blog.iphone-dev.org/

You can re-use redsn0w v0.8 we released a few weeks ago to jailbreak today’s 3.0.1 update. Just let iTunes update or restore you to official 3.0.1 then run redsn0w. The only “trick” is that when redsn0w asks you to identify the IPSW used, point it at the 3.0 IPSW instead of the 3.0.1 one. After the jailbreak, reinstall ultrasn0w 0.9 if you need the unlock.
 
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