Iphone 4 will not recognize US Sim cards?

Discussion in 'iPhone Tips, Help and Troubleshooting' started by Zero1994, Mar 6, 2012.

  1. Zero1994 macrumors newbie

    Joined:
    Feb 28, 2012
    #1
    I bought a used iphone 4, and it will not recognize any us sim cards. Apparently it was used in mexico (found out after purchase) and im being told that it needs to original sim in order for me to be able to use it? that doesnt make sense to me. Im pretty sure the phone is locked to AT&T, could there be some sort of lock on it for only international use or something? any help would be greatly appreciated.
     
  2. Applejuiced macrumors Westmere

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #2
    Its not locked to AT&T. If it was you'd be able to activate it with any AT&T sim.
    And no, AT&T doesnt put any locks on their phones for international use only.
    My guess is its a iphone that is locked to a Mexican carrier or maybe another carrier outside the US.
    Also even if you had a sim from the original carrier its locked to you would just be able to activate it and get to the homescreen.
    You still wouldnt be able to unlock it and it wont recognize or accept any other sims but only from the carrier its locked to.
    So either way you look at it its a lost cause.
    Just my 02.
     
  3. Zero1994 thread starter macrumors newbie

    Joined:
    Feb 28, 2012
    #3
    Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)

    Is there a way to check and confirm that it's locked to another carrier? And if it is would it have to be unlocked for it work in the us? (I know It can't unlock it as of now)
     
  4. normanbates macrumors regular

    Joined:
    Aug 24, 2011
    #4
    Phones from Mexico will not accept US sims unless it is unlocked.

    This is because networks lock handsets using the MCC MNC info stored on the SIM.

    MCC stands for Mobile Country Code and MNC is Mobile Network Code.

    So even if AT&T have operations in Mexico the US SIM will not work because when you put the SIM in the first thing it will check is the MCC of the SIM. It will compare it against the one it is locked to, in this case Mexico, and if they don't match it will not allow network access.

    MCC for Mexico is 334 and the US MCC is 310 so as you can see they don't match.

    Even if AT&T have the same MNC in every country they don't control the MCC so their only other option would be to have the handsets unlocked to all networks so that you can put any AT&T SIM in
     
  5. Zero1994 thread starter macrumors newbie

    Joined:
    Feb 28, 2012
    #5
    Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)

    Thanks for the detailed response!! It sucks that I bought this phone and can't use it! Is there any way I can actually confirm that this is a phone that is carrier locked in Mexico? Because if I can confirm that then at least I can try selling it around here for that purpose.
     
  6. TriJetHero macrumors 601

    TriJetHero

    Joined:
    Oct 13, 2010
    Location:
    World
    #6
    just wait for a SIM Interposer for 4.11.08 BB.

    Or sell
     
  7. Applejuiced macrumors Westmere

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #7
    I'd sell it the way it is.
    You wont be able to tell exactly to what carrier its locked to.
    Maybe someone can use it for parts or have someone at the Apple store swap it out for a refurb if they lie their way through that.
     
  8. Zero1994 thread starter macrumors newbie

    Joined:
    Feb 28, 2012
    #8
    Yeah thats what im going to do, i actually found out what carrier it was locked to, because the seller said they had the original sim and it went through the activation with it, and to my luck, the phone is worth more in Mexico than it is for a regular iphone 4 in the US, so even though i wasted some time, i might make it out with some extra cash and another iphone 4. Thanks for everyone who helped me out!
     
  9. Applejuiced macrumors Westmere

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
  10. Zero1994 thread starter macrumors newbie

    Joined:
    Feb 28, 2012
    #10
    Thanks man
     
  11. normanbates macrumors regular

    Joined:
    Aug 24, 2011
    #11
    Depending on your Baseband and if you're still on 5.0.1 you can unlock the device via Ultrasn0w v1.2.5

    If you don't know how to find your baseband here's how

    Tap Settings>General>About

    Scroll down to Modem Firmware, that is your baseband.

    If it matches any of the following you can jailbreak and unlock

    01.59.00
    04.26.08
    05.11.07
    05.13.01
    05.12.01
    06.15.00

    You'll first need to Jailbreak via Redsn0w v0.9.9b9 then use Ultrasn0w v1.2.5

    If you want to try this the tutorial is here

    http://www.redmondpie.com/unlock-io...ne-3gs-using-ultrasn0w-1.2.5-how-to-tutorial/
     

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