Prerequisite: Your device should be on build JZO54K prior to doing anything.
There are two methods to updating your tablet, besides just waiting.
The first is using a custom recovery like TWRP or CWM. This is the simplest and easiest way to do it. Just download the appropriate file for your device, place it on your device memory, reboot to recovery and flash. Pretty simple and straight forward.
The second method is to sideload it using ADB. This is not one that a noob should probably attempt.
You will need the latest ABD version installed on your PC. Snag the right file from down below and place it in a folder on your desktop. You will have to reboot your Nexus 7 or Nexus 10 while holding the Volume Down button to get to the Fastboot Menu. When you see the word START, use the volume keys to navigate to “Recovery” and use the power button to select it.
You will now see an awesome Android with a red exclamation icon. You will then press the Volume Up and Power button together and be taken to another menu. using the volume keys again go to “Apply update from ADB” and select it.
Once you are this far along, plug you tablet into your PC using your USB cable. Now comes the real fun. Open a command prompt in the same folder where you saved the file. In windows it is shift and right-click and then select “open command window here”. Enter the following commands for your device.
[For Nexus 7 Wi-Fi] – adb sideload 6ece895ecb23.signed-nakasi-JDQ39-from-JOP40D.6ece895e.zip
[For Nexus 10] – adb sideload eaef14432ff5.signed-mantaray-JDQ39-from-JOP40D.eaef1443.zip
Then just wait and you are done. It will tell you when it is done at the bottom ” Install from ADB complete”. Then simply reboot and enjoy Android 4.2.2. Not our favorite way to manually install an update, but some people prefer this method over others. Snag which every file you might need for your corresponding tablet below.
Check out the sources for some great images of what it all looks like.
P.S. AndroidSPIN takes no responsibility for what you choose to do on your device. If you go through the mentioned methods and suffer failure, divorce and jail time, that is your fault. Always do your research before attempting to do anything.