Nexus devices running on the Android 6.0 Marshmallow can now root without modifying the system partition, which makes it easier to apply the OTA update. Though, currently an experimental feature, Chainfire’s latest SuperSU (SuperSU 2.56 Beta) can give root access on Nexus 5/5X, Nexus 6/6P, Nexus 9 & Nexus 7 2013 running on Android 6.0 without modifying the system partition.
The guide given here let you know how to root a Nexus phone (Nexus 5, 5X, 6, 6P, 9 and 7 2013) on Android 6.0 Marshmallow without modifying the system partition. Before you get start, please note that this is an experimental feature, so it might have many bugs that have not been fixed yet. Also, a factory reset will unroot your phone.
The main benefits of this rooting method, according to Chainfire are, it is easier to unroot, unlittered/system partition, OTA’s are slightly easier, and most importantly it will not soft brick your device.
Root Nexus Devices on Android 6.0 without Modifying System Partition
Warning: This is experimental. Rooting your phone should do with extreme care; otherwise you will end-up with a bricked device. Backup data on your phone.
Disclaimer: Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components. It is recommended for technically talented users only.
1. This method requires unlocked bootloader and TWRP custom recovery installed on the phone. Also, if you have already rooted, you have to reflash your stock /system partition. Also, setup ADB and Fastboot on your PC.
4. Connect your Nexus phone to your computer and issue the below command:
adb reboot bootloader
5. Once your phone boot into bootloader mode, flash the modified boot image by issuing the below command:
fastboot flash boot boot.img
6. Once done, reboot your phone by selecting the ‘reboot system’ option.
7. Now, boot your phone into TWRP recovery mode and flash the SuperSU zip file by taping ‘Install’ button. Then reboot your phone.
You can read more about this root method and discuss at the XDA thread [HERE]. If you come across any issue, leave it in the comment section below.