Even if you do not necessarily look at the iPhone 7 and iPhone 7 Plus outwardly, but Apple has reworked the devices fundamentally. For the first time, the two models have a stereo loudspeaker, do not have a headphone connection anymore, and the home button also had to have a capacitive version. The latter brings some profound changes. For example, the forced restart will work differently, but the DFU mode will now be slightly modified.
To put the iPhone 7 (Plus) in maintenance mode
Make sure the latest version of iTunes is installed on your computer. Connect your iPhone 7 or iPhone 7 Plus with your Lightning cable to your computer. Turn off your iPhone as usual. Press and hold the power button on the right side of your device for three seconds before pressing the volume down button on the left side of the device.
Hold down both buttons simultaneously for ten seconds. If you see the Apple logo, press and hold the buttons for too long and restart the process. After 10 seconds, release the power button and hold down the Volume Down key for another five seconds. If you see the iTunes logo on your iPhone, you have left the button too long and must restart the entire process.
If your screen is black, you have successfully put your iPhone 7/7 Plus into DFU mode. You should also be notified of the DFU mode in iTunes. In DFU mode, for example, you can reset your iPhone to factory defaults or downgrade.