I have an Iphone 3G from UK 02 and got it jailbroken by someone. Today I accidently updated it
using the automatic update tool in itunes and now it's been locked. The following is a screenshot
of what I am faced with.



I then tried to jailbreak and
unlock it myself using the guide at Jailbreak iPhone 3G on iOS 4 With RedSn0w but I am stuck
in step 3 where I have to "update" my iphone from 4.1 to 4.0.

I downloaded the ipsw file but I don't know how to install it on the iphone.
Any help and advice would be much appreciated. (I'm using a macbook for your kind reference).

Originally Posted by G5P7

I am stuck
in step 3 where I have to "update" my iphone from 4.1 to 4.0.

Your statement does not make sense.

iOS 4.1 has not been released yet. So it's not possible you "accidentally" updated to iOS 4.1

Did you mean iOS 4.0.1? or iOS 4.0.2?

As you have a 3G, you don't need to downgrade from 4.0.2 or 4.0.1 - you simply need to run redsn0w 0.9.5 BETA [iPhone Dev Team] redsn0w 0.9.5b5 and when redsn0w asks for an IPSW point redsn0w at a 3G 4.0 IPSW

This is clearly explained on the official redsn0w page, don't trust other sites that might have their facts wrong.

Once you jailbreak with redsn0w, reinstall ultrasn0w to unlock.

Note this ONLY works if you accidentally upgraded to any iOS 4.0.x version. Accidental upgrades to iOS 4.1 (which will be released I think tomorrow) will destroy your chances to unlock. That includes anyone who tried an iOS 4.1 beta.

All this has been explained in other threads on this forum. Please search before you clutter the forum with duplicate threads.