The aim of this thread is to make an easy guide to flashing stock firmware. Owners of previous nexus devices already know all this stuff, this thread is aimed at making the process as simple as possible for new users. This will work regardless of what modifications you've done to your device. Remember to backup all your important data and do this with the knowledge that all flashing activity carries some risk.
Download
Factory image here
(for windows users) Minimal adb & fastboot
(for mac users) adb & fastboot for mac
Follow the instructions to install adb on your computer.
Prepare your tablet
Enable developer options in settings > about tablet and tapping build number 7 times
Open developer options and enable usb debugging. (If you haven't unlocked your bootloader yet, tick enable oem unlock)
Extract images
Place the downloaded factory image inside your adb folder and extract with 7zip.
A new folder will be there called something like volantis-lrx21. Open and extract "image-xxxxx-zip" to your adb folder. We are interested in these files:
bootloader-flounder-xxxxxx.img
boot.img
recovery.img
cache.img
system.img
vendor.img
Place these files directly into your adb folder.
# I recommend renaming the 'bootloader-flounder-xxxxxx.img' to just 'bootloader.img' to make it easier to type.
Now that everythings set up, we can start flashing
Plug in your device. Open the adb folder, hold shift and right click and select open command window here
(if your having driver issues try using Pdanet)
Run these commands one at a time
adb devices
adb reboot bootloader
if you haven't unlocked the bootloader yet run
fastboot oem unlock
and follow the instructions using the volume keys to scroll through the menu. This procedure will wipe all data.
Run the following commands one at a time
fastboot flash bootloader bootloader-flounder-xxxxxxx.img
(replace 'bootloader-flounder-xxxxx.img' with full name of bootloader image)
fastboot reboot-bootloader
fastboot -w
fastboot flash boot boot.img
fastboot flash recovery recovery.img
fastboot flash cache cache.img
fastboot flash system system.img
fastboot flash vendor vendor.img
(OPTIONAL) At this stage you can relock the bootloader if you want by running the command
fastboot oem lock
finally reboot the device by running
fastboot reboot
Thats it. Enjoy your tablet in factory condition
adb & fastboot for mac