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  1. Thread AuthorThread Author   #1  
    burstroc's Avatar
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    Default Unlocking a Japanese iPhone 4s to use in the U.S.

    Hi everyone,

    I have been living in Japan for several years and just recently had to move back to the U.S. I have an iPhone 4s I purchased from Japanese carrier AU KDDI, and I'm wondering what I need to do to be able to use it with a U.S. carrier. From what I've read online you need not only to jailbreak the phone and replace the SIM card but also remove the SIM lock and while I am familiar with the first two processes I'm not as sure about the third. Can anybody walk me through this? The phone is just under a year old and still works perfectly so it seems like a waste to replace it even if I can do so fairly cheaply.

    Thanks!
  2. #2  
    Karenkcoulter's Avatar

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    Default Unlocking a Japanese iPhone 4s to use in the U.S.

    It's possible that the phone is unlocked and all you need to do is get a new SIM card. In most of the world, I know people pay full price rather than the subsidized price in the US, so phones are often sold unlocked.

    If the phone is locked, but not under contract the first thing I would try would be to contact KDDI.

    Otherwise you may want to check on eBay for unlock services. I know for AT&T phones, you can pay someone to unlock it for you that doesn't involve a jailbreak. Something similar may exist for KDDI.

    If none the above pans out, I'm sure someone can help you with the jailbreak/unlock process.
  3. #3  
    tawnytodd's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    Removing Sim lock means you free your mobile from a particular network and use any network in your phone.Locked phones are cheaper than unlocked ones.This is just a way of business trick by the mobile network providers to increase their user count.Unlocking a phone(Remove sim lock) means you unlock your mobile from the particular network to which your mobile is locked.Now you have to unlock it from Japanese network to use the mobile with U.S network.
    You can unlock your iPhone using remote unlock methods which is more reliable and less risky .The unlock process will be done by the network provider or by any 3rd party code provider available online.
  4. #4  
    3cit's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    Quote Originally Posted by tawnytodd View Post
    Removing Sim lock means you free your mobile from a particular network and use any network in your phone.Locked phones are cheaper than unlocked ones.This is just a way of business trick by the mobile network providers to increase their user count.Unlocking a phone(Remove sim lock) means you unlock your mobile from the particular network to which your mobile is locked.Now you have to unlock it from Japanese network to use the mobile with U.S network.
    You can unlock your iPhone using remote unlock methods which is more reliable and less risky .The unlock process will be done by the network provider or by any 3rd party code provider available online.
    only two months late on this one, but getting better
  5. #5  
    kch50428's Avatar

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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    Quote Originally Posted by burstroc View Post
    Hi everyone,

    I have been living in Japan for several years and just recently had to move back to the U.S. I have an iPhone 4s I purchased from Japanese carrier AU KDDI, and I'm wondering what I need to do to be able to use it with a U.S. carrier. From what I've read online you need not only to jailbreak the phone and replace the SIM card but also remove the SIM lock and while I am familiar with the first two processes I'm not as sure about the third. Can anybody walk me through this? The phone is just under a year old and still works perfectly so it seems like a waste to replace it even if I can do so fairly cheaply.

    Thanks!
    Unlocking the SIM on this device is irrelevant... while AU/KDDI is a CDMA provider, Verizon will not activate an iPhone4S that was not OEM'ed by Apple for Verizon. That's just the way it is.

    If you live in a locale with a US military presence- you'll likely be able to find someone about to PCS to Japan that might like a phone they can activate/use there and you'll recoup the cost of getting a Verizon iPhone4S if you want to keep that... or go with the iP5.
    Keith - iMore Moderator - The Mobile Nations/iMore Forum Rules
     iPhone5 on VZW;  iPad(2012) - wifi with BadElf for GPS
    "When the debate is lost, slander becomes the tool of the loser." -- Socrates
  6. #6  
    margaretoak64's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    I had the exact same problem with an iphone4s from AU KDDI that my brother gave me, which he used for just a couple of months while he was in Japan. There is absolutely no way you can unlock that phone to use it outside of Japan apparently. He was at the AU KDDI office in Tokyo yesterday and that's what they had informed him. I can't tell whom to blame for this, AU KDDI or the Apple, but it's absurd that they locked it so that one would have to buy a whole new phone when one moves from Japan. Surely Apple should be able to override this plan/phone lock from Japan, but they said "No". Guess why? They'll be able to sell more iphones this way every time one leaves Japan. Pretty greedy and powerless for a multi-billion $ company!
  7. #7  
    kch50428's Avatar

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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    You might try a US based CDMA prepaid provider that would activate that AU KDDI device... or, as I noted above, you could likely easily sell it to a US service member about to PCS to Japan and use those proceeds toward a device you can activate on your account.
    Keith - iMore Moderator - The Mobile Nations/iMore Forum Rules
     iPhone5 on VZW;  iPad(2012) - wifi with BadElf for GPS
    "When the debate is lost, slander becomes the tool of the loser." -- Socrates
  8. #8  
    natasftw's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    Quote Originally Posted by kch50428 View Post
    Unlocking the SIM on this device is irrelevant... while AU/KDDI is a CDMA provider, Verizon will not activate an iPhone4S that was not OEM'ed by Apple for Verizon. That's just the way it is.

    If you live in a locale with a US military presence- you'll likely be able to find someone about to PCS to Japan that might like a phone they can activate/use there and you'll recoup the cost of getting a Verizon iPhone4S if you want to keep that... or go with the iP5.
    There was only one hardware version for the 4s. What makes you so sure unlocking the SIM won't make it accessible on GSM networks as the other 4s phones are? It isn't like other versions of the iPhone that have different radios between GSM and CDMA models.
    ups925 likes this.
  9. #9  
    Richard Swart's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    I have iPhone 4S locked to kddi
    Tryed to kddi to unlock it they no
    I'm in australia now and have it unlocked by a gpp sim and still using it works perfect
    It will work on any gsm carrier world wide
    Everything works just like factory unlock all for$12au
    So hope this helps
  10. #10  
    chills18's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    Hi! I'm in the exact same situation. Just moved back to Australia with my iPhone 4s locked to KDDI Au.

    Can you pass on the details for the working GPP sim you bought? There seems to be so many dodgy websites around that I can't tell what seems actually genuine...
  11. #11  
    natasftw's Avatar
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    Default Re: Unlocking a Japanese iPhone 4s to use in the U.S.

    I'd imagine he means: He posted nearly a year ago meaning you're unlikely to get a response from him.

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