I saw on Sinful it's possible to go to 4.1 and preserve my existing baseband, so doesn't that mean it's safe to upgrade? Or does that mean that I can upgrade but it won't be able to jailbreak after upgrade? My understanding is that if it preserves the BB that it's able to still be JB'd after. I'm not so concerned with losing unlock (since mine is a UK Factory unlocked iPhone 4, lol)... but don't want to lost my JB. Sorry for the redundancy in the question, but there's not a lot of info on factory unlocked devices and guidance as to what's ok. Thanks!