I keep seeing these sketchy-looking websites selling 'factory' unlocks for iPhones, but I always thought that they were a scam. But, last week I was reading up a thread on reddit, where this one guy said that he got his phone factory unlocked this way. So, I decided to buy one of these 'factory IMEI unlocks' on ebay for 2.50£. Although the listing was for AT&T, the guy told me over private message that he can unlock most carriers, and that all he needs is the IMEI as well as the name of the carrier. I bought this service, and a day later, he unlocked the iPhone 5. Now, my question is the following: how on earth do they do this? I read somewhere on macrumors that they just call the mobile operator repeatedly until they give the unlock code, but this seems quite unlikely to me. Another place they said that they 'hacked' into the unlock servers or something... but it still stumps me. The thing is, I repair iPhones and offer jailbreaking + JB unlock, but I recently noticed that one of my local competitors was offering a factory unlock instead of JB unlock, so I was wondering if this is something that works everytime or not. I'm not in the US if anything.