I have an unlocked iPhone 4 from Europe but I've moved to the US two months ago. I'm using it on AT&T without a contract. The phone has been acting weird lately - with almost little to no usage, the battery only lasts 5 hours or so after being fully charged. I calibrate the battery and all take care of the phone. My question isn't about how to fix that, but in case I decided to go get an exchange at the Apple Store - will I preserve the unlock? Some say 'Yes, you'll get a new unlocked iPhone, in the same status you gave it to them', while others say 'You bought the phone in Europe, you can't exchange the phone in the US' So, what's the verdict? p.s. I know this is asked often, but like I said - some say yes and some say no.