These are the instructions people must follow to root Google Nexus 6P smartphones when they are running on the Android N NPD56N Developer Preview 4 software updates. The tutorial makes use of a custom recovery image and flashes the systemless version of the SuperSU app which lets you completely unroot just by taking a factory reset.
- People must unlock the Google Nexus 6P bootloader before they can continue on and install a custom recovery on the smartphone.
- We only recommend following this guide on the Google Nexus 6P smartphone. The files involved might vary on the other Google Nexus devices. Likewise, you should only follow this for the Android N NPD56N update. It will not necessarily work for other updates in the Android N range.
- You need to have a custom recovery installed on the Google Nexus 6P smartphone  before you can flash the SuperSU found in this guide that makes people the root user.
BEFORE WE BEGIN
- It is always best for people to backup the Google Nexus 6P smartphone before going ahead with something like rooting the Android operating system that is running on it. Everyone can get that done any way they like, including from within the custom recovery partition that we are accessing in the guide. Alternatively, people might prefer checking out the Helium for Android application from the Google Play Store.
HOW TO ROOT GOOGLE NEXUS 6P RUNNING ON ANDROID N NPD56N DEVELOPER PREVIEW 4
- Download the SuperSU 2.71  on the computer and do not unzip the file.
- Connect the Google Nexus 6P smartphone to the computer with the USB cable that is usually used for charging the battery.
- Copy the SuperSU version 2.71 over to the internal storage SD card and then unplug the smartphone from the computer when that is complete.
- Turn off the phone and then reboot the Google Nexus 6P into the recovery mode  by holding the same hardware button combination as the regular stock recovery and it will boot up the custom recovery partition because you replaced the stock version of the custom version already.
- Tap on the backup button from the custom recovery menu and take the NANDroid Backup people did not take a backup already before starting with the guide.
- Tap on the Install button from the main recovery menu and follow the guidelines to browse through to the SD card and then select the SuperSU version 2.71, so it is ready to be flashed.
- Swipe the bottom of the display to confirm the SuperSU installation and then wait for it to be installed entirely.
- Choose the option that says it is going to reboot the system from the main recovery menu and then wait for it to reboot into the regular mode.
In conclusion, that is how to root Google Nexus 6P smartphones when people have them running on the Android N NPD56N Developer Preview 4 software builds. The SuperSU is the same variety as the one from the Marshmallow updates in the sense that it is still a systemless root which means it no longer goes through the /system partition. That is a good thing for you if you like to have a cleaner rooting method and would prefer being able to unroot by taking a hard reset.