Android 7.1 Nougat on Nexus 7 2012 WiFi

1. Backup / transfer personal data (texts, photos, videos, apps, etc)
   
   
2. Read [ROM][7.1.0_r5][NDE63U][Grouper|Tilapia][F2FS/EXT4]Android 7.x AOSP by AndDiSa
   • download aosp_grouper-7.1-ota-eng-20161127.ds.zip (219 MB)
   • check MD5 signature (FCIV or a similar tool):

     fciv -add aosp_grouper-7.1-ota-eng-20161127.ds.zip -md5

3. Install Android SDK / platform-tools
   
   
4. Install TWRP (Team Win Recovery Project) for Nexus 7 2012 Wifi
   (twrp-3.0.2-0-grouper.img, 2016-04-04, 93 MB)
   
   Follow Fastboot Install Method (No Root Required) section.
   
   
5.  Boot into recovery mode (TWRP) with:
   

   adb reboot-bootloader

   Use Volume Up or Down keys to select "Recovery Mode", then press "Power".
   
   
6. Now in TWRP, choose Wipe > Swipe to fatory reset
   
   
   
   
   
7. Back to TWRP main screen > Advanced > ADB Sideload > Swipe to Start Sideload
   
   
   
   
   
8. Sideload new ROM from your PC:
   

   adb sideload aosp_grouper-7.1-ota-eng-20161127.ds.zip
   Total xfer: 1.00x

   
   
   
   
   Note:  E: unknown error [log] causes or implications are yet unknown, ignoring for now.
   
   
9. Go to Open GApps, choose ARM + Android 7.1  + Pico.
   • download open_gapps-arm-7.1-pico-20161205.zip, 5 December 2016, 121 MB
   • check MD5 signature (FCIV or a similar tool):

     fciv -add aosp_grouper-7.1-ota-eng-20161127.ds.zip -md5

10. Sideload Open GApps:
    • go back and reselect Sideload option
    • select Wipe Dalvik Cach
    • Swipe to Start Sideload

    adb sideload open_gapps-arm-7.1-pico-20161205.zip
    Total xfer: 1.19x

    
    
    
    
    
11. Reboot (TWRP Main > Reboot > System).