Nougat on Grouper

Who would believe that the Nexus 7 (2012) 32GB WiFi tablet is still selling for $200 on ebay?! I mean, this thing is already 4 years old! I found someone selling it for $35 on Gumtree, so I immediately snatched it up.

Latest factory image for nakasi (a.k.a. grouper) is Android 5.1.1 (LMY47V). A check on XDA-Developers show that there's an unofficial AOSP 7.1.1_r4 Nougat build for it, so guess which one I went for?

Before anything anything else, given that this is a stock device, you have to first unlock the bootloader, root, and install a custom recovery. All these are done with WugFresh's Nexus Root Toolkit. Just tell NRT what Nexus device you have, and on what software level, and it will take care of downloading all the files that you need from the Internet. Remember to enable USB debugging on the device first!

If NRT/adb cannot detect your tablet when connected to your PC's USB port, you might have to download and install the Nexus 7 USB drivers:
https://developer.android.com/studio/run/win-usb.html
https://androidmtk.com/download-google-nexus-usb-drivers

If the drivers won't install properly on Windows 8.1 or Windows 10, you might have to disable Driver Signature Enforcement:
https://www.youtube.com/watch?v=Z6HbmjXONuk

Download ROM, 7.1 pico Gapps, and SuperSU here:
http://forum.xda-developers.com/nexus-7/development/rom-android-7-aosp-grouper-t3467514
Gapps have to be pico or else it won't fit in the /system partition given the size of the ROM.
With SuperSU, we'll be doing a systemless install (via recovery) to prevent potential bootloops.

In summary, here are the steps:

1. Enable USB debugging on N7 (via Developer Options) and connect to PC via USB.
2. Using NRT, unlock bootloader. Takes a loooong time for the N7 to boot up. Have patience.
3. Enable USB debugging again.
4. Again using NRT, root and install customer recovery.
5. Boot to recovery using NRT's Advanced Utilities.
6. Wipe --> Factory Reset. You might also want to Format Data if you want to start fresh with no leftover crap.
7. Reboot to system. At this point, you can copy the ROM, Gapps, and SuperSU zips to the device via MTP.
8. Again, boot to recovery using NRT's Advanced Utilities.
9. Flash ROM and reboot to recovery.
10. Flash Gapps and reboot to recovery.
11. Mount the /data partition, if not already mounted.
12. Open Terminal and enter the following command: # echo "SYSTEMLESS=true" >/data/.supersu
13. Close Terminal and flash SuperSU.
14. Reboot system.

Enjoy that Nougat goodness on your grouper!