This Android Marshmallow CM13 Nightly firmware is only downloadable for Nexus 7 tablets.
Download ASUS Nexus 7 USB Drivers on your computer and have USB debugging enabled.
Install a custom recovery tool e.g TWRP or ClockworkMod, then perform a Nandroid backup on your device.
The Nexus 7(2013) bootloader should be unlocked and the tablet powered up to 80 to 85% level.
- On your computer, Download CyanogenMod Android 6.0 CM13 Nightly custom ROM and Nexus 7 Google Apps zip files.
- Mount the Nexus 7 to the computer then copy both the zip files to your phone’s SD card root folder.
- Turn off your tablet then switch it to bootloader mode. Simply power ON the device while holding down the Volume and Power keys. Follow the instructions on the screen, tap BOOTLOADER and then navigate to RECOVERY.
- Perform a factory reset to wipe the tablet’s data.
- Clear the cache memory by choosing the “wipe cache partition” option
- Go back to the ClockworkMod Recovery menu>> Advanced >> wipe dalvik cache. This procedure prevents boot loops and errors in the installation process.
- Return to CWM Recovery screen menu >> install zip from SD card >> choose zip from sdcard, navigate to the Android M ROM .zip file then confirm the installation process.
- Redo the above step to install the Google Apps zip file on your Nexus 7 (2013) tablet.
- On install completion, select “+++++Go Back+++++” then ClockworkMod Recovery menu>>reboot system now; then wait for your device to restart.
On restart, the ASUS Nexus 7 tablet is now updated to the Android Marshmallow CM13 Nightly custom ROM. Navigate to Settings then tap “About tablet” to confirm.