Versions of Android later than Kitkat (4.4.4) seem to run really slowly (even after factory reset) on my Google Nexus (2012 version) tablet. So after some reading of the Google docs I downgraded to Kitkat.
Here are the steps I took in case anyone else needs to do the same. Note this will wipe all your data so make sure everything is backed up first.
- Install android tools with sudo apt-get install android-tools*
- make a folder called android to store images in your home directory
- Download KTU84P from https://developers.google.com/android/images to ~/android, I also downloaded the image my tablet was currently using so I could revert if neccessary, which was LMY47V (5.5.1)
- Extract the tar ball
- Enable USB debug mode in Android Developer settings
- Make sure your tablet is unlocked and powered on
- Run adb devices to check your device is listed (if not repeat above steps to enable USB debug mode)
- Run adb reboot bootloader to reboot your tablet into Android bootloader
- Run fastboot oem unlock to unlock the tablet so we can flash the OS
- Run ./flash-all.sh in the extracted OS directory (~/android/nakasi-ktu84p for me). This will install Kitkat 4.4.4 and reboot your tablet.
- Run fastboot oem lock, as a safety measure.
Enjoy your much more responsive tablet, and learn to not just trust upgrades in future I’ve learned it’s best to see what people are saying about the performance first when you’re tablet isn’t the latest and greatest version any more.