iOS 4.0 [TEST] Downgrade iPhone 4/3GS iOS 4.0.2 to 4.0.1 WITHOUT SHSH BLOBS

Discussion in 'iOS Jailbreak & Cydia' started by mikeac, Aug 30, 2010.

?

Did it work?

  1. YES! :D

    6 vote(s)
    50.0%
  2. No... restoring to 4.0.2. :(

    6 vote(s)
    50.0%
  1. mikeac

    mikeac Member

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    iPhone 4 (Black)
    One thing...

    I AM NOT RESPONSIBLE FOR ANY BROKEN DEVICES.

    I have not tested it yet. But if you want to, you have nothing to lose since you are on 4.0.2 with no blobs saved anyways.

    Step 1:
    Download the iOS 4.0.1 ipsw.

    Step 2:
    Extract it with your preferred program. You may need to rename the firmware file from .ipsw to .zip to do this.

    Step 3:
    Open the buildmanifest.plist with a plist editor. Search and replace all – 8A306 with 8A400. Save. Repeat the same with the file restore.plist.

    Step 4:
    Download iOS 4.0.2 ipsw and open this with your programs GUI. Do NOT extract it. Just open it with the GUI and leave it open. You must use this exact file and not create a new one. If you have to create a new one for reasons like you are on OS X, then use zip command line not explorer or finder to make the zip. I will assume you are using the original file opened in WinRAR for the rest of this guide.

    Step 5:
    Take all the files from the extracted iOS 4.0.1 and drag them over to the iOS
    4.0.2 archive window that you have open.

    Step 6:
    Delete all the .dmg files that have 002 at the end, leaving only the 001 files left.

    Step 7:
    Save the archive, and rename it back to .ipsw if you changed the name to get your program to open it.

    Step 8: Mac: Using Finder, click on “Go to Folder” menu “Go” and type / etc /. Copy the file “hosts” file on your desktop then open it with Text Edit and at the end of the file add the string: 74.208.10.249 gs.apple.com
    Always save the file on your desktop and then drag it back into the folder “/ etc”
    Windows :Go to Start, All Programs, Accessories and click Notepad with the right button, select “Open as Administrator”. Now go to ~ / Windows / system32 / drivers / etcand open the hosts file, adding the end of this line: 74.208.10.249 gs.apple.com
    Save the file.

    What this does is send iTunes to Saurik's server so it confuses iTunes when it verifies the firmware.

    Step 9: Put the device in DFU mode. Make sure it is off and plugged in the computer. Hold the power button until you see the Apple Logo, then hold the home and power button for ten seconds, and release the power button but continue to hold the home button until iTunes recognizes your device in recovery mode.

    Step 10:
    Now simply open iTunes and restore the firmware you changed.
    This is it, you should now be able to restore from a backup, jailbreak and unlock your device on iOS 4.0.1 with JailbreakMe and ultrasn0w.

    Now you should delete the string from the hosts file.

    Again, if this does not work, don't blame me. I found this guide floating around the internet. This does not work with any other firmware or device please do not ask if this works for anything but iPhone 4/3GS on iOS 4.0.2.

    If you DID get this to work, please post proof and answer the poll. If you DIDN'T get this to work, tell me. If many people can't get this to work, I will delete this guide and request closing/removal of this thread.

    Guess what. The likelihood of this working is actually good. Because currently 1/3 of you have /most likely/ saved your SHSH blobs. XD

    If you know for sure you or someone else has NOT saved your blobs in Cydia or on TinyUmbrella, and this guide worked, please post here.
  2. mikeac

    mikeac Member

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    It appears to work for a couple people. Please tell me if you have tried this, and if it worked.
  3. slim21st

    slim21st Active Member

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    how can i change the ipsw to .zip?

    windows 7 and it only shows firmware name... no .ipsw
  4. apple10

    apple10 Member

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    Wow. I would try this cept i have an ipt3g
    I already have SSH for 3.1.2-4.0.2 but out of curiosity:
    Would this work on an iPod touch 3G?

    Ahh... Nvm/ just saw the part that says it wont work on any other device so not to ask... Sorry
  5. MuseFan25

    MuseFan25 Member

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    4G iPod touch
    that has already been proven to not work.

    Code:
    There is much discussion on many blogs about a potential means of downgrading iOS 4.0.2 to 4.0.1 by simply changing a couple values in the buildmanifest.plist and copying all of the images from 4.0.1 into 4.0.2 and then deleting the files ending with 002. Following all of this, perform a DFU restore and somehow you will be on 4.0.1.
    
    
    There is a perfectly logical explanation for all of this and I will lay out exactly what is happening and explain why it is working for the folks that are the lucky ones.
    
    
    Let me get this out first.
    
    1. This is not a miracle, at least not in the sense you all hope for
    2. SHSHs are STILL required for any iPhone 4, iPhone 3GS, iPad, iPod Touch 3G, and iPod Touch 2G (MC Model)
    3. There is NO way around this... unfortunately this method included.
    
    Let me start by explaining something very important. The buildmanifest is used by iTunes to build much of the TSS request that is used to obtain your SHSH for any given firmware revision. Unfortunately, the BuildNumber has no part to play in the request for SHSH. All that you ended up doing in following these directions is request 4.0.1 SHSH blobs. THAT IS ALL. Since every single one of you that got this to work changed your hosts file to point to Cydia, Cydia responded to the TSS request with an SHSH blob that was ALREADY "on-file". There was no magic. There was no miracle, apart from the lucky break that your device had been put on Cydia's SHSH request list at some time in the distant past.
    
    
    That's it in a nutshell folks. There was no amazing technique for bypassing Apple's TSS. There was no amazing exploit that exists in DFU mode allowing for 4.0.2 -> 4.0.1 downgrading. It's simple; Cydia had your SHSH because at sometime in the past either:
    
    * Someone saved your SHSH with that device using TinyUmbrella and the default options
    * Someone restored that device with Cydia in the hosts pointing to gs.apple.com
    * Someone jailbroke the device and pressed 'Make my life easier'
    
    That's it folks. Sorry to be a buzzkill but there was much confusion about this issue and many blog posts that simply didn't give the full story of what exactly was going on. 
    Source
  6. lukage

    lukage New Member

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    4G iPod touch
    I can't downgrade my iPod touch 1G
  7. mikeac

    mikeac Member

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    Im pretty you should post this elsewhere. :/
    ------------------double post merged------------------
    Thanks for that. But somehow a miracle happened for four people.

    Please Register or Log in to view images

  8. babosayshi

    babosayshi New Member

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    Yessss!

    FINALLY!!! after getting my iphone 3gs i immediately wanted to jailbreak it so i get home and get to it only to realize that my firmware (4.0.2) cant be jailbroken AT ALL! after searching for three days for a way to downgrade it seemed that i was SOL until i saw this and gave it a try. at first it didnt work cuz i didnt write out the "host" file how it was posted but after fixing that it worked like a charm! thank you very much for this post it seriously made my weekend! thanks again!
  9. sanga282

    sanga282 New Member

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    make windows show extensions

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