Flashing a Nexus 7 to Android Lollipop

Recently I got to take a Nexus 7 tablet running Android 4.4.4 KitKat and flash it up to Android 5.0.1 Lollipop. It took me a while at first, but had I known which image was correct to use, I could have completed this task in probably less than 15 minutes.


Here are some terms to cover:

Root - Gaining root access to a device. Then you're able to run the sudo command/enhanced privileges.

ROM - Modified Android version.

Flash - Installing a new ROM or kernal onto a device.

Brick - "Break" device during flashing or rooting. Device will appear non-responsive or not allow any actions. Most "bricked" devices can be fixed.

Bootloader - Runs the code necessary to start the operating system.

ADB - Android Debug Bridge. Communicate between computer and Android device.


Here's some software to get first that we will use:

Minimal ADB and Fastboot - http://forum.xda-developers.com/showthread.php?t=2317790

Nexus Root Toolkit - http://www.wugfresh.com/nrt/

Nexus Factory Image - https://developers.google.com/android/nexus/images

      Note: I got the razor 5.0.1 image. Yours may vary depending on model.

Many great Android resources. If you get stuck, ask here - http://forum.xda-developers.com/


Now we can get started.

USB cable and Nexus 7 ready to go

Install the Minimal ADB and Fastboot. Install the Nexus Root Toolkit from above.

Note: It is possible to do this without the Nexus Root Toolkit. I think it's way easier though using the toolkit and will be more friendly to users that haven't rooted devices before. If you're interested in these methods, Google is your friend.

Nexus Root Toolkit 

Plug the Nexus in via USB and let the drivers automatically install. I'm using Windows 7 and had no issues.

On your device, go to Settings > About Device > find Build Number.

Tap on the Build Number section multiple times until it tells you that Developer Mode is enabled.

Go under Developer Mode > Enable USB Debugging and make sure it is checked.

Now we can unlock the bootloader on the device to allow us to flash our images onto the device.

Open Nexus Root Toolkit. Click the Unlock button > click OK > chose Yes.

Chose yes when this appears on your device

Your device may reboot a few times. When it is booted back up. go to the Settings menu and enable Developer Mode and select USB Debugging again.

Go back into the Nexus Root Toolkit and chose Flash Stock + Unroot. Pick the option to use an image that you've already downloaded.

Once you tell it to install give it some time to complete. It will look like this:

Flashing the Nexus 7

Note: If the above screen gives you an error about signature mismatch, you most likely have downloaded the wrong factory image. This happened to me and my Nexus was "bricked" as it would not load anything. It looked like this:

Uh-oh

If this happens, hold the power and up volume keys down until the device shuts off. Now hold the power  + down volume in at the same time so that the device enters Fastboot mode. Now go back and download a different image to try. You can leave the device in Fastboot mode while you go back into Nexus Root Toolkit and go through the Flash option again trying the new image you downloaded.

For more on Fastboot mode, see: http://www.android.gs/how-to-enter-google-nexus-7-fastboot-mode/


Once completed, your device will reboot. This process may take 5-10 minutes so just let it do its thing.

Once rebooted you should see the setup screen:

Congrats!

Now you will go through the initial setup, connecting to wifi and adding your Google account in.

You will be left with a 5.0.1 device running Lollipop! Check About Tablet under settings to verify.

5.0.1 running! 

   

Lollipop in action