how to get DFU mode on iPhone 8, iPhone 8 plus,and iPhoneX

1. Quick-press the volume up button.
2. Quick-press the volume down button.
3. Press and hold the power button until the screen goes black.
4. Release the power button once the screen blacks out, then ...
5. Quickly press and hold both the power and volume down buttons together for 5 seconds.
6. After 5 seconds, release the power
   button without letting go of the volume down button.
7. Continue holding down the volume down button for at least 5 seconds.