Doing a mistake is so human, upgrading our iOS is no exception to which we are left with iPhone 4 on baseband 4.11.08, therefore you can not unlock it using Gevey Sim unlock tool.
But don’t lose hope yet, as a wonderful news just appeared recently from AppleNBerry, the name who develops Gevey SIM unclok tool, has announced publicly via its Facebook that they have reached a final stage in developing their unlock tool and they will be releasing the baseband 4.11.08 unlock tool sometime. In other word, the unlock tool for iPhone 4 on 4.11.08 baseband is underway.

However, don’t ask me when exactly the tool will be release or its ETA, as for those queries, no one knows but the AppleNBerry itself of course God Knows Best. Anyway here is their announcement via Facebook.
updates..updates…
I thought I made it clear, but I guess there are some miscommunications.
Good news, we are in the testing stage.
Bad news, I don’t want to promise anyone and get flame.
It is very difficult to not offend anyone.
So be patient, wait until they come out with the good news to unlock the iPhone 4 on baseband 4.11.08. But I believe it won’t be long, as it’s said they are in the testing stage, means if everything is settled the 4.11.08 baseband unlock tool will be presented to us!
Or you can use another tool which is CutYourSim to unlock iPhone 4 baseband 4.11.08.
And as for iPhone 4s there is a tool that works like Gevey SIM, it is a promising iPhone 4s unlock tool TPISM Interposer offered that you can try but it’s not a free offer.
