Lets face it..After months of waiting, we still don’t have any real unlock for 04.11.08. Applenberry are working on gevey sim 2 for almost two months and they are nowhere near unlocking 04.11.08 baseband. Recently, there are some rumors regarding chinese servers which allows you to downgrade your baseband. This, however, is very difficult to achieve as mentioned by Saurik (Creator of Cydia) on his blog post. 
There are some people/groups on twitter claiming unlock/factory unlock for iPhone 4 04.11.08 baseband. None of them actually works for now. If you know of any such people/group, please mention them in comments and we’ll ask them for a sample unlock to prove their authenticity.
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I haven’t really read and heard any of these rumors so I can’t judge the situation.
there are some videos in youtube saying its possible to unlock 04.11.08 but only on ios 5.0.1 i duno if its true. It has something to do with a redsn0w patch. Just search in youtube. regards from portugal