So I have iPhone 3Gs which I recently jailbrok(produced in 2010). It had iOS 6.0 and now I downgraded it to iOS 4.1 with 06.15 (iPad) baseband. Now, as I read, I need to downgrade to 05.13 (iPad) baseband so that I could unlock it. I tried using this tutorial (hxxp://senseiphone.com/unlock-baseband-05.16.07-iphone3gs-ios6-10095279/) <- new user, cannot post links. Although all passes without error, when I go to settings -> about it still says 06.15 baseband !

Any idea why this happens ?