Is there any way I can unlock an iPhone 3G with Firmware 4.2.1 and baseband 05.15.04?

I correctly installed Cydia and Ultrasn0w (under iOS 4.1.2 or something like that if I remember right) via JailbreakMe 2.0.

The Unlock seemed to work, but I accidentally updated to 4.2.1.

Is there any way I can fix this?

  • What OS are you using?
    – Doc
    Aug 9, 2011 at 15:20
  • I'm using OSX 10.7
    – Denshi
    Aug 9, 2011 at 15:24
  • 1
    You should have googled this. First hit I got: osxdaily.com/2010/11/28/…
    – user10355
    Sep 9, 2011 at 18:59

2 Answers 2


How about the legitimate way through AT&T:


  • Not everybody is using AT&T though, especially not outside the US.
    – nohillside
    Nov 7, 2013 at 6:15
  • Start with the carrier, if the phone is not subsidized and the account is in good standing they will more than likely provide the "Factory Unlock." You can also tell them you are planning to travel overseas and plan to use a local cell provider while traveling. This approach has work for several people I know. AT&T has had so many requests for this they created an on-line form and I was simply using this as an example. Nov 7, 2013 at 6:28
  • You could edit your answer to include the relevant information you have provided in the comments.
    – M K
    Nov 7, 2013 at 7:11
  • Indeed. You are also answering a question that is over years old. Back in a time when carriers weren't unlocking iPhones at all, under any circumstance. Times they are a changing.
    – user10355
    Jan 16, 2014 at 7:01

You can find out how to jail break and unlock your 3G on mac here. You may need SHSH blobs, but I didn't see where in the tutorial. I think SHSH blobs are only for downgrading.

  • Is there any other Way than upgrading to 06.15? I thought about that before and neither want to loose my warranty nor my gps. And yes, as far as I know are SHSH blobs for downgrading the Firmware(but not the Baseband).
    – Denshi
    Aug 10, 2011 at 12:31
  • You've already jail broken your device, so as far as apple is concerned, you're no longer covered under warranty. Technically, since you're currently on an approved firmware, you would be warrantied as long as the prior jailbreak didn't leave residue files on the device that apple could see. As soon as you jailbreak the phone again, you won't be warrantied. You can't have your cake and eat it too. As far as the baseband, I have no idea if there is another way - probably not. If you're unlocking, you're using an unapproved carrier and not covered anyway.
    – skub
    Aug 10, 2011 at 13:09
  • SHSH blobs only used to downgrade the actual OS. They do not downgrade basebands. You cannot revert to an older baseband unless Apple still signs that particular version of the OS. And they have stopped signing 4.1.2 a considerable time ago.
    – user10355
    Sep 9, 2011 at 18:58

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