[Nexus 7 Q&A, Help & Troubleshooting] nakedtruthishere:
This is the situation, probably many of you guys are in:

A Nexus on stock Android, rooted with wugfresh´s Nexus Toolkit and an outstanding Android Update (like recently from 4.3 "Jellybean" to 4.4 "KitKat"), which won't work the OTA way.

So what to do? Going back to stock, update Android and reroot the device will wipe all your data and lead to a lot of frustrating detail work even when there are backup tools like Helium and others available.

Searching the web for a possible way to upgrade Android I found this blog: click. Obviously there is a way to manually update without loosing data and preferences, there should be an automatically one as well.

Well, I didn´t find a fully auto-update function (there may be one, but I couldn´t find it), but it is really easy work.

What do we need?

- A PC with wugfresh´s toolkit installed and up to date for your Nexus device

- Winrar decompression tool

- Google´s factory image for your device

- USB chord of good quality, the china charger-only ones may not work properly

Follow the instructions step by step:

- First, make sure, the Nexus Toolkit is up to date and switch to the model and Android version running on your device.

- Download from Google´s site the factory image applicable for your device you want to upgrade to.

- With winrar installed on your PC, doubleclick on the downloaded factory image, typically something like "<filename>.tgz". After some time Winrar will open a separate window showing the table of content of the package. Doubleclick on the file symbol showing up. Another list will appear.

- Drag'n drop the file beginning with "bootloader..." to your desktop

- Doubleclick on the "image...zip" file in Winrar application window. Unpacking will start and a second Winrar window will appear in foreground.

- Drag and drop "boot.img" and "system.img" to your desktop as you did before.

- After having now all 3 files we need on your desktop, close both Winrar windows.

- Now open Wugfresh´s Nexus Toolkit. Make sure, all drivers are properly installed. To check, click on "Full Driver Installation Guide -...", skip Step 1 and 2 and perform the "Full Driver Test" in step 3. Proceed if it works, otherwise start again with step 1.

- Now start the "Advanced Utilities" in the lower left corner of the toolkits main window. Click on "Launch" Button. Disregard the bunch of buttons you see and stay fixed to the middle row. Switch the upper radio button to "Flash (Permanent)".

- With your device plugged in, click on the "Bootloader" button. Select the bootloader...img from your desktop, when your asked to and confirm. Lean back and let things work. Your Nexus will boot and reboot.

- Having finished that, proceed with the "Boot" button and select the boot.img from desktop this time. Your device will boot and then turn black and stay black. Don´t worry, wait a while until you are sure the process has finished, unplug and then push the power button of your device for more than 10 seconds, it will switch off. Push and hold VOLUME DOWN and POWER at the same time and your device will reboot in FASTBOOT mode with the little green robot as good as dead.

- Plug in the USB Chord again, choose "System" in toolkit window, confirm the system.img on desktop, lean back and pray. Jokin...

- Wait and see the new start animation for the first time. Let the toolkit work until it confirms you are done with nearly all work.

- Go back to the main window of the toolkit and choose "Root". I´m not really sure, if this is necessary, but I did it all time. Follow the instructions given and voila, you will have Android 4.4 on your device without having lost any data.

- If necessary, update the SUPERSU App on your device. Start the app, preferences, prepare for new installation and reinstall the newest issue from Google Market.
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