Downgrading from 4.2 to 3.1.3- Possible?

Discussion in 'iPhone Tips, Help and Troubleshooting' started by ckc, Nov 25, 2010.

  1. ckc macrumors regular

    Nov 13, 2010
    I am using a factory unlocked 3gs (32GB) which since being upgraded to ios4.1 and now the latest 4.2.1 has suffered from calls always terminating after 2-3 minutes into a call.

    This never happened using 3.1.3 and other family phones on 3.1.3 do not have this problem.

    Is it possible to jailbreak the 4.2.1 firmware and downgrade it to 3.1.3. I appreciate a jailbreak for 4.2.1 may not yet be available, but when it is will it be possible to downgrade it?

    Otherwise any other Ideas other than going into an Apple store here in the UK. The phone is out of warranty.
  2. jackryan57 macrumors regular

    Nov 29, 2008
    I had the same issue here. iPhone 3Gs running 3.1.3 - never had a problem with it in over a year. Updated to 4.1 and instantly had issues, phone would shut down randomly, wouldn't restart unless plugged into external power, battery suddenly showing empty even though it was full. The biggest issue though was the random shut downs, it rendered my phone useless. Go to apple dot com and read the user forums on the 3gs - 129 pages of people with the same issue. Apple is well aware of the issue.

    I called apple care and began a three week ordeal with them. My phone was also out of warrant. I didn't give up, I kept telling them that this was caused by THEM not by me - my phone worked fine before the 4.1 and that wasn't a lie. Finally after three weeks they granted me a "warranty exception" and agreed to replace my phone - they made me a genious bar appointment and I went in and got a new 3gs and haven't had a single issue - I am so happy.

    Keep calling them and they will give you a new phone - also to answer your other question, I had it jailbroken and did a downgrade to 3.1.3 but it did not fix the issue, I learned that once you hit the 4.0 versions it will leave some crumb behind even with a downgrade - so the problem will persist. Just make sure to do an erase all content and settings and do a clean restore so no trace of the jailbreak is there when you visit apple store.

    Good luck and don't give up- they will give you a new phone.
  3. PsstGreek macrumors 68040


    Oct 21, 2010
    Tampa Bay
    Only if your iPhone was jailbroken before in the past and you saved the shsh files for 3.1.3. That's the only way you can downgrade back down.
  4. OBAMANIZER macrumors newbie


    Nov 25, 2010
    Just make note that your baseband will have been upgraded so you won't be able to do a carrier unlock using ultrasn0w.
  5. Nermal Moderator


    Staff Member

    Dec 7, 2002
    New Zealand
    And why exactly would there be any reason whatsoever to do a software unlock on a factory-unlocked phone?
  6. eastercat macrumors 68040


    Mar 3, 2008
    Actually, Tiny Umbrella doesn't require your phone to be jb. However, if you haven't save your SHSH blobs, downgrading isn't going to happen. Since 3GS, Apple has been authenticating each iOS; these blobs fool Apple's server.

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