iOS 17 Downgrade: Guide to Rollback to iOS 16

Check the iOS version: Make sure the previous software version is still signed by Apple. If you are trying to downgrade your device to an iOS version it no longer supports, you might face unwanted issues.

Check the Internet Connection: An inconsistent internet connection is another prominent cause of this error. It happens when the download of the iOS update is halted in between (due to a poor connection). Go to your phone's WiFi settings to further diagnose this.

Force restart your device: By applying the correct key combinations, we can forcefully restart an iOS device and resolve this issue. The steps to do this vary by iPhone:

● iPhone 8 and Later: Quick-press the Volume Up button first. Let it go and quick-press the Volume Down button. Subsequently, hold the Side button and let it go once the phone restarts.
● iPhone 7/7 Plus: Press and hold the Volume down button and the Sleep/Wake button simultaneously. Keep pressing them until the Apple logo appears.
● iPhone 6, 6s Plus, or iPhone SE: Press and hold the Sleep/Wake button and the Home button simultaneously. When the Apple logo appears, release both buttons.

Connect it to iTunes: In no time, iTunes will automatically detect that your device is in recovery mode and display the setup prompt. Confirm your choice and restore your device to factory settings to fix this.

Check whether your iPhone is jailbroken: Mostly, users get this error while performing an iOS 17 downgrade on a jailbroken device. If your device is jailbroken, then you should not use iTunes to downgrade it. Instead, use a readily available tool like TinyUmbrella or FutureRestore to do the same.

Boot your iPhone in Recovery Mode: You can also take the assistance of iTunes and boot your device in Recovery Mode to resolve this problem. Just connect the iPhone to your computer and open iTunes. Then, forcefully restart your device using the correct key combinations (already listed above). Subsequently, iTunes will detect as soon as your phone boots in the Recovery Mode. When you get the setup prompt, click on the "Restore" button to reset your device.

Check the IPSW file: Firstly, make sure that you have downloaded the correct IPSW file from a trusted source. Also, the IPSW file should be compatible with your iOS device. Else you might face this issue.

Disable Find my iPhone: Before connecting your device to iTunes, make sure that the Find my iPhone feature is disabled. To do this, go to its iCloud Settings > Find my iPhone and turn off this feature.

Update iTunes: You should use an updated version of iTunes to downgrade iOS 17. Launch iTunes on your system and go to Help > Check for Updates. This will make iTunes check for any available updates.

Force restart your device: This will reset the present power cycle of your device and will let you fix any minor issue related to it. To do this, you need to press specific keys on your device (already listed above).

Use a 3rd party tool: If nothing else seems to work, consider using a dedicated iOS repairing tool like Dr.Fone - System Repair (iOS). It can fix all kinds of iOS and iTunes-related issues without causing any harm to your device. Just launch the application and follow a simple click-through process to put your phone out of the loop and downgrade it to a stable iOS version.

Use an SHSH blobs dumper: There are tons of readily available third-party SHSH dumpers (like iFaith) that you can try. Though, most of these applications will require a jailbroken device. You can simply connect your device or provide its model to obtain an ideal SHSH blob.

Obtain your device's SHSH blobs: Connect your iPhone/iPad to your computer and open iTunes. Then, select your device and go to Summary. Next, click on the "Serial Number" field until it displays the ECID number. Now, copy the ECID code and go to any online source to convert it into hexadecimal code. Next, open TSS Saver, and input your ECID and Model Identifier. Finally, click Submit and download your SHSH2 blobs.

Use a data recovery tool ASAP: If you have suffered from an unwanted data loss on your device, then take the assistance of an iOS data recovery program. A part of the Dr.Fone toolkit, it is one of the first and the most successful data recovery tools for iOS devices. All you need to do is connect your device and launch the application. Then, follow a simple click-through process to extract all kinds of lost or deleted data from your device. The application will let you preview the extracted data and selectively save it to the location of your choice.

Use a Data Restore Tool: You can load a previous iTunes or iCloud backup using an iOS restoring tool and preview its data on its interface. For instance, to restore an iCloud backup, you simply need to log in to your iCloud account. The application will list the available backup files for you to pick an ideal option. In this way, you can easily restore your data without erasing the existing content on your device.