The much-anticipated Apple iOS 17 has been unveiled! As Apple releases new iOS versions, it will also stop signing some older iOS versions. This means that sooner or later, your current iOS version will no longer be supported and you may have to upgrade your iPhone to a new firmware version.
However, every iOS update comes with its downsides and often bring some problems like iPhone battery draining fast, iPhone keeps freezing, iPhone charging problem, etc. One way to solve the problem associated with iOS update is to move back to a known stable version, in other words, downgrade iOS version. But what if Apple has stopped signing the version you intend to downgrade to? How to restore and install unsigned IPSW of that version? This guide will give you all the answers!
Part 1: What is Unsigned IPSW?
IPSW is the file extension of Apple’s iPhone mobile operating system. An unsigned IPSW means Apple has stopped supporting the iOS version. iOS users will not be able to restore to unsigned firmware using iTunes.
Due to security concerns, Apple will periodically unsign iOS version and encourages users to use the new features offered by new iOS version updates.
However, new versions of iOS software often cause unpleasant experiences to device performance and functionality. To resolve firmware update errors and problems, reverting to a previous stable iOS version is a common solution.
Part 2: Is It Possible to Install Unsigned IPSW?
Yes, you can restore your iOS device to unsigned IPSW firmware. But not through the traditional way like iTunes.
Normally, when you want to upgrade or downgrade iOS version using IPSW restore file, you will do it through iTunes.
During the downgrade process, iTunes will make some verifications and checks with Apple servers to ensure you are restoring a signed IPSW file. Anyone trying to install unsigned IPSW firmware through iTunes will only get an error message such like this firmware is not signed. This means you cannot restore to it in iTunes.
To downgrade to a previous iOS firmware that has stopped being signed by Apple, the basic requirements are:
a third-party restore software
the unsigned iOS IPSW file
SHSH blob file
Part 3: How to Restore Unsigned IPSW?
Fortunately, even though Apple periodically stops signing some older iOS versions, if you have saved unsigned IPSW through an online tool like TSS Saver, you can still use a restore tool like FutureRestore to restore and install unsigned IPSW. Let's talk about how to do that.
Method 1: Restore Unsigned IPSW with SHSH2 Blobs
It is possible to restore unsigned IPSWs with the help of SHSH2 Blobs. These blob files are the digital signatures that Apple places on each IPSW firmware file for each iOS device. When Apple stops signing a particular firmware, it removes the sign (signature) from the firmware so users won't be able to downgrade to it.
You must have saved a blob (digital signature) file of the iOS version you want to restore while the version is still being signed by Apple. Once Apple stops signing an iOS firmware version, the signature is removed, and then, you can't restore the firmware.
Online tools like TSS Saver can help with blob saving. You can start saving the digital signature of your current iOS firmware now for possible future use. For how to flash unsigned IPSW files, see the steps below.
Step 1: Connect your iPhone to your Mac or Windows computer using a data transfer cable.
Step 2: Open iTunes on your PC and navigate to the iPhone device information page by clicking the mobile icon at the top screen. Keep clicking on Serial Number until ECID appears. Copy the value next to it.
Step 3: Go to TSS Saver website. Enter your ECID, choose your iPhone model and click Submit. The online tool will automatically save the blob of all available iOS firmware for your iPhone device and provide you with an option to download any of them.
Step 4: Referring to the image below, insert your ECID value and click Submit to see all blob files you've previously saved.
With your blob files ready, you are halfway done with restoring unsigned iOS. The next section will show you how to use the unsigned IPSW restore tool to restore unsigned iOS versions.
Method 2: Restore Unsigned IPSW via FutureRestore
FutureRestore is a tool developed for iOS users who want to restore, upgrade, or downgrade to any iOS version that is no longer signed by Apple. But FutureRestore can't do the job alone. It needs the help of other files:
The destination unsigned iOS IPSW file you're restoring to.
The blob file of the destination iOS firmware (which you've learned how to save and retrieve in the previous section).
The recent version of FutureRestore.
To restore unsigned IPSW file using FutureRestore, follow the steps below:
Step 1: Connect your iPhone to PC, making sure your PC has an internet connection.
Step 2: Put all the 3 items listed in the requirements into one folder.
Step 3: Open up Terminal on your Mac computer or Command Prompt on Windows.
Step 4: Drag the unarchived FutureRestore file into Terminal and type -t.
Step 5: Drag the blob file into the Terminal interface and type --latest-sep --latest-no-baseband (if your iPhone is no sim) or --latest-sep --latest-baseband (if your iPhone has sim).
Step 6: Drag the unsigned iOS firmware into the Terminal screen as well. Your terminal or Command Prompt interface should look like the one in the image below.
Step 7: Press Enter and let the downgrade process begin and complete.
Step 8: If the log on the Terminal screen indicated that the process is stuck and failed at recovery mode, simply reenter the line of codes and try it again.
Now you have already installed unsigned iOS versions successfully.
Method 3: The Easiest and Fastest Way on iOS Downgrade
While using these unsigned IPSW restore tool above will enable you to downgrade iOS, there is no denying the fact that it is indeed very complicated and risky. If you have a headache dealing with these specialized technical processes, then you have a better option - WooTechy iMaster, which is the easiest and fastest tool to downgrade iOS.
WooTechy iMaster is an iOS management software designed for iPhone/iPad, which performs quite well in iOS upgrade, iOS downgrade and iOS backup. As the most popular iOS downgrade software in recent years, it can quickly downgrade iPhone/iPad to any supported iOS version with a few simple steps, making the iOS downgrade process very easy. What's more, it guarantees that the downgrade process will not affect any of your data!
WooTechy iMaster - The Best Tool to Downgrade iOS
iOS Downgrade: Easily downgrade iPhone/iPad to any supported iOS version without data lost
iOS Upgrade: Quickly update iPhone/iPad to the latest iOS version
iOS Backup: Backup all data on iPhone/iPad for free
Support almost all iOS versions and latest iPhone/iPad models
Easy steps, Fast speed, and Secure
[Video Tutorial] How to Downgrade iOS?
How to Downgrade iOS with WooTechy iMaster？
Step 1: Download and install WooTechy iMaster on your computer. Launch it and connect your iOS device with USB cable. Click Downgrade iOS.
Step 2: Select the firmware version you want to downgrade to, click Next to download it.
Step 3: Once the firmware is downloaded and verified, click Start to begin the downgrade process.
Step 4: When the downgrade is complete, click Done. Now your device has been downgraded successfully.
Well, I believe this guide has taught you how to flash unsigned IPSW files via an online tool like TSS Saver and how to restore and install unsigned IPSW using a restore tool like FutureRestore. By now you should have downgraded your iPhone to your preferred and bug-free version of iOS!
It's worth mentioning that the much-awaited new Apple iOS 17 is finally unveiled! You can't miss this professional iOS upgrade and downgrade tool WooTechy iMaster anymore! If you encounter system failure or error after upgrading iOS 17 Beta, you can use WooTechy iMaster to quickly downgrade your iPhone to iOS 16 or any supported iOS version without losing data. Now this iPhone upgrade/downgrade software has also become the most popular tool for many Apple users to experience and switch iOS versions! Download and try it out!