there are a couple of sites you can type in your imei number to look up. google search is where i looked for sites.
i just tired iphoneimei.info but it said my sim lock was unknown. also said the same thing when i checked my iPhone 5.
since your on at&t, send a unlock request to att. https://www.att.com/deviceunlock/client/en_US/
I have unlocked three phones from ATT through iTunes. All three were able to use non-AT&T sims. If iTunes says it is unlocked, it's unlocked.I did that yesterday with ATT and did all the itunes instructions. Got the congratulations unlock message but I would like to verify it somehow as i'm going to sell it.
I have unlocked three phones from ATT through iTunes. All three were able to use non-AT&T sims. If iTunes says it is unlocked, it's unlocked.