cant put iphone 6Plus on DFU mode

Try again.

1. Connect your iPhone to a computer.
2. Make sure iTunes is running.
3. Turn Off your iPhone.
4. Press and hold down the Side button.
5. Press and hold down the Home button on the front of your device while still holding down the Side button.
6. Keep holding both buttons down for 10 seconds. (If you see the Apple logo, you've held them too long and will need to start again.)
7. Let go of the Side Button but keep holding the Home button for about 5 seconds. (If you see the "Plug into iTunes" screen, then you've held it too long and will need to start again.)
8. If the screen stays black, that's it! Your iPhone should now be in DFU mode.