Trying to downgrade your iPhone 4 to iOS 6.1.2 but kept on having issues? This post will explain why.

There are a bunch of reasons why people wish to downgrade their iOS but mainly it’s for the untethered jailbreak. For example, if you’re already on iOS 6.1.3 but wish to downgrade to iOS 6.1.2, you can only downgrade it IF you have your SHSH blobs saved. If you need to unlock your iPhone 4, do remember that downgrading your iOS will NOT downgrade the baseband. Your best choice for now is to get it officially unlocked.

A few weeks ago I wrote about how your SHSH blobs saved on Cydia are not being saved correctly and will cause restore issues. Saurik, the creator of Cydia came to our website and left a short comment on this issue. (That makes him the third iPhone celebrity hacker to come to my website after MuscleNerd and Sherif_Hashim).

We agree that’s he’s always busy with something and at the same time we’re also thankful for all his contribution to the jailbreak community.

A few days ago, he posted a lengthy article on his blog explaining the issue in great details. Mind you they are very technical so let me just summarize them in bullet points:

• Apple implemented multi-level and complex security checks during an iOS restore process, which may have contributed to this problem.
• Only A4-based e.g. iPhone 4 and older devices are affected by this issue.
• A5-based devices e.g. iPhone 4S are not applicable because there’s no exploit available to allow you to downgrade the iOS.
• If you attempt to downgrade from iOS 6.1.3 to iOS 6.1.2 with SHSH blobs from Cydia you will have a boot up issue even after there’s no restore error on iTunes.
• If you’ve used iFaith or redsn0w to save your SHSH blobs file on your local computer, that shouldn’t give you any issue when restoring your iOS.
• Saurik recommends that you save your SHSH blobs locally to avoid any potential issues in the future.

If you are still on iOS 6.0 and up to 6.1.2 on an iPhone 3GS, iPhone 4 or any A4-based iDevices, the safest way to dump your SHSH blobs is to use iFaith. The steps are outlined below:

How to Save SHSH Blobs using iFaith (Windows only) via jailbreakqa

iFaith supports iPad 1, iPhone 3GS (new bootrom), iPhone 4, and iPod touch 3rd and 4th generation. It does not support iPad 2, iPhone 4S, or older devices (iPhone 3GS with old bootrom, iPhone 3G, or iPod touch 2nd generation). As of April 2012, it may not work correctly if you have an 8 GB iPhone 4 (see here).

Step 1: Download iFaith

1. Download iFaith here: http://ih8sn0w.com/ (Note: iFaith may be detected as a Trojan by AVG and possibly other antivirus programs. This is a false positive and you may have to temporarily disable your antivirus program to use iFaith.)
2. Have your device plugged in and powered off.
3. Unzip the file and run the .exe file.

Step 2: Dump SHSH blobs onto your computer

1. You will see a welcome/warning screen. Click OK.
2. You are presented with 4 options. Select “Dump SHSH blobs” if you have not done so previously.
3. A screen will pop up telling you what devices are supported (Apple TV 2, iPad 1, iPhone 3GS, iPhone 4, iPod touch 3 and 4).
4. Click proceed then more credits, press let’s go!
5. Another pop-up will ask if you are dumping an Apple TV 2, so click the appropriate button.
6. Now, making sure your device is plugged in AND powered off, you can press the START button and put your device into DFU mode. iFaith will dump your current iOS device’s SHSH blobs onto your hard drive. The process takes about 10 minutes, and it may seem to hang on one part of the process, but be patient.
7. Once done, iFaith will ask you to save the blobs on your computer. I chose to make a new folder for this. Note that iFaith also stores your blobs on its own remote server.
8. iFaith will take you back to the main menu so you can build your signed IPSW.

Step 3: Build the signed IPSW

1. OK, now click on “Build signed IPSW”.
2. Click the “Browse for SHSH blobs cache” button. An Explorer window will open. Navigate to the folder that you had saved your blobs in the previous step – you should see a file that looks like this: iPhone_4-4.3.2_(8H7)-blobs.ifaith (here I am using 4.3.2 but yours will be whichever firmware you are using on your phone).
3. You will now be prompted to browse for the stock IPSW for this firmware. There is also the option to have iFaith download it for you if you do not have it on your computer.
4. Select the stock IPSW and iFaith will verify it.
5. iFaith will then build the signed custom IPSW for you and place it on your desktop.
6. You then can have iFaith put your device into PWN DFU for you if you want to restore your custom IPSW now, or just shut iFaith down if you are just building the IPSW for possible future use.
7. If you want to restore to your new custom firmware, just use iReb (included in the iFaith program) to get your phone into PWN DFU mode, close iFaith, open iTunes, press and hold the shift key and press restore, browse to the signed custom firmware you created with iFaith and press OK, then restore.

This may be a bit overwhelming for many, so I only have one advice for everyone. Whatever iOS version you’re on right now, just stick to it until the situation becomes clearer and there are going to be fixes soon.

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