(Last Updated On: June 21, 2020)
Doing a full restore on your iPhone is not a fun thing to do especially if you bump into issues like this. Try these different solutions which may save your iPhone.
In many occasions, you have to do a full iTunes restore on your iPhone to fix software related issues or if you need to sell it off. I don’t always like to do a full restore on iPhones because sometimes the process and result can be unpredictable and they are a challenge to fix. There are various error messages you can see on iTunes so for an average user, you will need a lot of time to figure out a fix if you encounter one or some of the errors.
“This iPhone could not be restored due to an unknown error (-1)” is probably one of the toughest one to fix because usually it is caused by hardware issues with your iPhone. The solutions below are possible fixes you can do at home without disassembling or taking apart your iPhone. As this issue is probably related to baseband chip corruption, the fixes below may not resolve it but it’s worth trying them yourself before attempting to send your iPhone to a repair center near you. This error occurs towards the end of the restore process which is also the same time when iTunes writes or updates your iPhone’s baseband.
Before you begin, there’s a quick way to identify if the problem is caused by hardware. On older iPhones such as iPhone 3GS or iPhone 4, you can restore it using custom firmware built using sn0wbreeze or redsn0w. The restore will usually go through without any problem. Once you can get to the Home screen, go to Settings, General, About and look for the IMEI. On an iPhone 4S or 5, there’s no method to restore it using custom firmware. However, in case you managed to restore it, on the Activation screen, tap on the (i) or information and it will show your the IMEI number.
If the IMEI is present that means there’s no baseband or hardware issue with your iPhone. If it’s showing blank that means it’s certainly a hardware issue so the solutions below will definitely not work.
Solution 1: Make sure that your iTunes is up-to-date
In order to check if you have the latest version of iTunes, launch iTunes and check for updates.
Windows: Choose Help > Check for Updates
Mac: Choose iTunes > Check for Updates
Simply donwload and install any available iTunes updates. Just be sure that you have an active internet connection.
Solution 2: Check that your computer’s operating system is fully patched and up-to-date
On a Mac, click Software Update from the Apple menu and install all available updates. On a Windows PC, go to the Microsoft Windows Update page.
Solution 3: Disconnect other USB devices that are currently connected on your computer
USB devices can sometimes mess up data communication between iTunes and your iPhone. Do the following:
- Disconnect any devices connected to your computer such as printers, scanners, dangling cords, card readers, cameras, and so on.
- Connect only your keyboard and mouse. Connect your iPhone directly with its cable.
- Launch iTunes again and try to do a full restore.
Please pay attention if you have a virtualization software or operating system installed, as it may create a virtualized USB port which may also cause issue.
Solution 4: Temporarily deactivate or uninstall antivirus software or firewall on your computer
Third party security software such as antivirus or firewall is designed to block certain data that may harm your computer. To prevent this from happening they must be kept up to date and properly configured to effectively protect your computer while still allowing an update or restore to proceed. If your computer uses a router on your local network, additional security policy applied on the router which may block some data that’s required to restore your iPhone.
Solution 5: Restart your computer
Sometimes a lot of issues can be fixed simply by doing a computer restart. If you have tried the above make sure you try this as well.
Solution 6: Possible hardware fixes (not for novice)
The solutions below are not meant for novice so proceed only at your own risks!
- Replace the dock connector
- Heat up the baseband CPU chip
I hope that one of the suggested solutions above may help bring life back to your iPhone again. Otherwise, your only choice is to get it fixed or replacement from Apple if it’s still under warranty.