what is dfu mode in iphone

DFU stands for Device Firmware Update, and it is the deepest type of restore you can do on an iPhone. It allows all devices to be restored from any state, and it is essentially a mode where the BootROM can accept iBSS. DFU mode is used to fix issues with the device, and it is even deeper than recovery mode. When an iPhone is in DFU mode, nothing will be displayed on the screen. iTunes will alert you that a device was detected in recovery mode. To enter DFU mode, you need to follow specific steps depending on the iPhone model. Once in DFU mode, you can perform a DFU restore, which reloads the software and firmware of your device. To exit DFU mode, you can force restart your device.