How To: Get into DFU Mode on your iPhone! 573,543 views573K views. 2 days ago · How to put your iPhone with Face ID into DFU mode · Plug in your iPhone with Face ID into your Mac or PC. DFU stands for Device Firmware Update which reloads the software and the firmware of your device. DFU or Device Firmware Upgrade mode allows all devices to be restored from any state. How To Put An iPhone In DFU Mode · Plug your iPhone into your computer and open iTunes if you have a Mac running macOS Mojave 10. As OS X Daily explained, DFU (Device Firmware Update) mode is a means to getting your iPhone to interface with iTunes without iTunes.