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  1. #1
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    Unhappy Help Please!! :((

    My gf have iphone4 and she upgrade it to ios 5.. and now it keeps saying "Invalid Sim" is there a way to fix that? And is there a possibilities that i can downgrade back to ios 4.3?? Or i can just delete ios 5 file and install ios 4.3 again?

  2. #2
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    Vivian's Avatar
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    You can, only if the iPhone is jailbroken and you have saved the blobs for iOS 4.3. There's unfortunately no other way otherwise.

    Try reinstalling iOS5?

  3. #3
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    what if not jailbroken?? is there any other way to downgrade or fix it??

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    Quote Originally Posted by haccerz12 View Post
    what if not jailbroken?? is there any other way to downgrade or fix it??
    You can download the firmware from a website and downgrade through iTunes. Download the firmware (if you tell me what carrier and what firmware it is I will find it for you ) and then connect your iPhone to iTunes then hold down "Shift" on your keyboard and press restore. Then find the firmware you downloaded and select it and iTunes should restore your iPhone to the firmware that you want! Or you could just press restore which would restore it to the firmware the phone came with! Hope I helped
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  5. #5
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    Quote Originally Posted by haccerz12 View Post
    My gf have iphone4 and she upgrade it to ios 5.. and now it keeps saying "Invalid Sim" is there a way to fix that? And is there a possibilities that i can downgrade back to ios 4.3?? Or i can just delete ios 5 file and install ios 4.3 again?

    I think that there must be some computation between the SIM number & the physical handset number (IMEI?) to determine if the carrier supports it and therefore display this message. This would have to be in an O2 system OR an Apple iTunes O2 system, I assume.

    Looks to me like iOS-5 upgrade has perhaps reverted to some old carrier records or changed the rules!

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    I had the same problem.

  7. #7

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    I have put the phone near a heat source in an effort to dry it out ovenight, in the vain hope that I may be able to get it to power up long enough to get it synced before the replacement arrives.