how to get iphone into dfu mode?

DFU mode is a mode that you can put iPhone into where it can interface with iTunes but do not load the operating system of iPhone or boot loader. DFU stands for Device Firmware Update.

DFU mode allows the iPhone to change the firmware on the device. This is the big reason why people need to access this mode. This can serve to downgrade to a prior iPhone firmware and operating system, or to use any other custom firmware that is required for a jailbreak or SIM unlock.

Here is a tutorial that allows you to place your iPhone in DFU mode.

2. Turn off and unplug your iPhone from the PC

3. Connect the iPhone to the PC and wait for the display of the boot image. The boot image and the grey Apple by default but may change if the iPhone has been jailbroken.

4. On the appearance of the image, you must simultaneously press POWER and HOME buttons. The power button is located on the top right of the iPhone and the HOME button in the middle bottom.

5. When the boot image disappears, we must continue to press both buttons for 2 seconds and release the power button only.

6. Hold the HOME button until the iPhone is recognized as being in DFU mode in iTunes.

DFU mode, the iPhone does not display picture but just a black screen.