ive unlocked 2 nokia lumia 520s now, its not free, but only cost .99 cents. takes anywhere from 5 min to 2 days to get the code but so far they have worked first try. If your interested ill post the ebay seller that does it. He is very good to work with and its well worth the 99 cents considering the websights ive been to are trying to charge anywhere from 28 -58 bucks for the same code. I KNOW i could call my carrier and get the code, but i decided to let someone with experience get the info for me rather than deal with automated messages and waiting to talk to someone. **__ to unlock your 520 with a SIM unlock, you MUST have a SIM from another carrier to put in your phone. It will read the SIM and report it is locked to your current carrier and then open the Unlock code screen--** far as i can tell this is the only way to get to the unlock screen..but i could be wrong.