currently there are 3 possible unlocks you can use, unfortunately the 3 are all SIM INTERPOSERS, (not software unlocks) first is the R-sim, second is the TPSIM, and lastly the ever famous Gevey Sim Ultra S, just google them to know more. *personally i would go with the Gevey sim since they made the previous Sim interposers for the iphone 4. The other two are just new in the Unlocking thing, so its not sure if its legit.