DFU (Device Firmware Update) is one of the two important modes designed in iOS devices. The another one is Recovery Mode, which has been explained in the previous post.
Why DFU mode?
We’ve known that Recovery Mode is used for restoring iOS devices when users accidentally encounter some issues that regular restore cannot fix, such as getting stuck in boot loop, getting stuck on the starting logo screen… And this mode only allows users to restore their device with the latest firmware.
The question is, what if you want to downgrade firmware or restore with any firmware that is still being signed? Well, this is the moment we need the help of DFU Mode.
Just like Recovery Mode, you can use DFU Mode if you encounter the same problems I’ve mentioned above. The difference is that you can downgrade or upgrade your device with custom firmware. You can go to IPSW, find the version you want, download and then restore the device with it. Of course, this is possible only if the selected firmware is still being signed by Apple.
Before proceeding, make sure you are using the latest version of iTunes and you have a backup of your data using iTunes or iClouds.
How to get into DFU mode
iPhone 6s and earlier:
- Connect your device to your computer using a cable and launch iTunes
- Turn off the device
- Hold the power button for 3 seconds, you’ll see the Apple logo screen.
- Begin holding the Home button without releasing the Power button for 10 seconds
- Release the Power button and continue holding the Home button until you see a message showing up in iTunes informing you that your device has been detected.
- Now your device will be in DFU mode, the screen will be totally black. If you have anything on your display, it means you are not in DFU mode yet. You’ll want to try again from the “Turn off the device” step.
Since the physical home button has been replaced with a Force Touch-based Taptic Engine on iPhone 7, the method to get into DFU mode has also been changed, but not too much. The procedures are the same with iPhone 6s and lower, but you have to use the lower volume button instead of the Home button.
How to exit DFU mode
To exit DFU mode, simply hold down the Power button and the Home button at the same time for at least 10 seconds, until you see the Apple logo.
How to install firmware using IPSW File
- Go to ipsw.me, select your device and download the signed firmware. If you download the firmware that is not signed anymore, you cannot restore to it in iTunes.
- Once it’s downloaded, connect your device to the computer, launch iTunes and put your device into DFU mode.
- Hold the Shift button on the keyboard and click the Restore button on the iTunes interface. You should see a new window that allows you to select the downloaded firmware. Once you select the file, iTunes will start the restore process.
While restoring, the device might boot several times in between the progress. Please don’t disconnect the phone from the computer till the progress is complete and you see the welcome screen on your iPhone.