The home button is no longer an actual button in the all new iPhone 7. Almost all the features are still accessible through the home button except for one. When all else fails with an iOS device, you can force a reboot by holding down two buttons simultaneously: the power/standby button and the home button.
However, starting with the Apple’s iPhone 7, that particular combination will no longer work. It’s likely that the iPhone needs to be turned on so that the new home button works as intended.That said, the home button on the iPhone still retains the same features you expect it from it, including Touch ID, Apple Pay, Siri, multitasking and reachability. The home button can also still be used to get out of apps and return to the home screen, and can be used to take a screenshot.
Here are full instructions on how to reboot and enter DFU mode on the iPhone 7 and 7 Plus.
How to reboot your iPhone 7:
Press and hold down the On/Off button on the right side
While continuing to hold the On/Off button, press and hold the volume down button on the left side of your iPhone.
Hold both buttons as the screen turns off, and keep holding them until the screen turns back on and displays the Apple logo.
How to put your iPhone or iPad into DFU mode:
Plug in your iPhone 7.
Make sure iTunes is running.
Turn Off your iPhone 7 if it isn’t already.
Press and hold down the On/Off button on the right side of your device for 3 seconds.
Press and hold down the volume down button on the left side of your iPhone 7 while still holding down the On/Off button.
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.)
Let go of the On/Off Button but keep holding the volume down 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.)
If the screen stays black, that’s it! Your iPhone 7 should now be in DFU mode.