How to Install Android 5.1.1 (Lollipop) on Nexus 7 (2012) without OTA or ADB Sideload + Root & Recovery! (UPDATE!)

UPDATE: Lollipop 5.1.1 has been rolled out to the Nexus 7 (2012) WiFi tablet. Google's page provides very little help in updating the tablet, and while there are a few articles that explain it better, it is still a hassle. The method described here is still the easiest and safest method to install the update...

I love the Nexus 7 (2012) tablet. Not because it's the best, or because it has features others don't. Simply because it has so much support, even from Google! There are so many good tricks for it such as gaining the ability to do Miracast, or enabling 3G data (on the WiFi version). The "trick" I'll be doing today is how to easily upgrade to Lollipop. Just remember, there are always some risk involved in these techniques, however they are minimal, and if you do everything correctly you should be fine.

Android 5.1 (Lollipop), Root & Recovery

DISCLAIMER:  This is for the Nexus 7 (2012) WiFi tablet. If you decide to try this with the mobile data (or the WiFi) version, you assume all responsibility.

OTA & ADB Sideload
When I first found out that the Nexus 7 had received Lollipop, I was pretty excited. I was already on KitKat, and wasn't sure that an official Lollipop build would even come anytime soon given its age (among other factors). I immediately looked up some articles to find an easy way to get Lollipop onto my Nexus 7. Many of the articles - which are usually just copies of each other - were stating two methods: OTA (Over The Air update) and ADB (Android Debugging) Sideload.

I had already rooted and was on a custom ROM, so OTA was out of the question unless I went back to a stock factory image and updated. The second method seemed a bit less time-consuming, but I was wrong. After downloading the files necessary and getting to my recovery's ADB option, the ADB interface would not start through my recovery. Just my luck.

I then figured out an even simpler method that should work for anyone, rooted or not...

Nexus Root Toolkit
The first thing you will need to do is download the Nexus Root Toolkit. It is a fabulous toolkit that works for all Nexus devices. It is fairly intuitive, if you are already familiar with the workings of rooting and ROMs.

1. Download the newest file here.
2. Install the program and allow it to check for updates.
3. A message about choosing your Nexus device and ROM will come up. Choose "Nexus 7 (WiFi Tablet)".
4. Click "Apply".
5. It will then pop up with the main menu.

Google & ADB Drivers
The first thing you need to do in preparation for the below method, is to ensure that your computer can see your Nexus 7 when connected by USB. If you do not see it in Computer (My Computer), then either the drivers you have aren't working correctly, or you don't have them.

To install the Google drivers:

1. Open Nexus Root Toolkit.
2. Select the "Full Driver Installation Guide - Automatic + Manual".
3. Click tab "Step 3".
4. Push the "Google Drivers" button.
5. Install the "Google Drivers" by clicking "Next" in the window that appears, and confirming any other prompts.

You should now be able to see the Nexus 7 from Computer as a viable device with storage.

If you already have ADB drivers installed, and cannot get ADB to recognize (authorize) the device, ensure that you have enabled USB debugging in "Developer Options" in the "Settings" menu. If not:

1. Click on the Settings app.
2. Select "About tablet".
3. Click on "Build number" area 7 times (it will count it down for you).
4. Go back into the "Settings" menu.
5. Select "Developer options".
6. Check off "USB debugging".

Note: If you already have "Developer options" as a selection, you do not need to perform steps 2-4.

If you still cannot get ADB to recognize your device, or you checked off "Always allow from this computer" on the RSA fingerprint prompt every time you plug in your Nexus 7 to your computer (as this caused a lot of issues with my LG G2), or if you have never done anything with ADB before, follow these steps:

1. Download the ADB Driver Installer.
2. Install the ADB Driver Installer.
3. Once completed, a window should pop up showing your device. If there is an issue with it for ADB, it will show a red stop sign-like image.
4. Click "Install" to give a successful green.

Note: If nothing shows up in ADB Driver Installer, or it is already green, then there are likely other issues going on (i.e. driver conflicts, faulty cable, etc.).

OEM Lock
If you are already rooted and/or using a custom ROM, you can skip down to obtaining Lollipop. Otherwise, we need to unlock the bootloader. You may also want to backup all your data first as this procedure will wipe all data:

1. Open Nexus Root Toolkit.
2. Click on the "Unlock" button.
3. Follow and confirm any prompts.

Your phone will likely turn off and boot back up a couple times during this procedure. It should be completely automated, so you should not have to do anything but wait.

Android 5.1 (Lollipop) Factory Image
While there is already a ROM with the ability to keep your current root and recovery, it is not the official stock factory image. The OTA method is by far the easiest of the three to do, but it can be very time consuming, especially if you haven't been upgrading. The ADB sideload method should be the fastest, but if you are not experienced with it (or able to use it like in my case), then you might want something that is more automated. This method will use the official Google factory image to install Lollipop.

If you haven't already, download the Nexus Root Toolkit and install it or you will not be able to perform the following:

1. Connect the Nexus 7 via USB to your computer.
2. Click "OK" when you see the RSA fingerprint on your tablet.
3. Open Nexus Root Toolkit.
4. Click on the "Flash Stock + Unroot".
5. Click "OK".
6. Select "NAKASI-GROUPER: Android 5.1.1 - Build: LMY47V".
7. Select " Automatically download + extract the factory image above for me." This is under "Choice". If it cannot, choose to download manually and it will provide a link to download from. A message to browse for the image will already have popped up. Browse for the downloaded image and select it. Then click "OK" to proceed. The image should then merge into the Nexus Root Toolkit.
8. Click "OK". The Lollipop factory image will then download. Once done, Nexus Root Toolkit will check for ADB status...
9. If successful, the Nexus Root Toolkit may also try to download TWRP recovery. If it is not, you will go through the same additional steps above required if you cannot download it automatically.
10. The Nexus 7 should then turn off and go into bootloader as it tries to flash the rooted boot image. It will boot up again, but leave it alone. The tablet will turn off again and go into bootloader as it tries to flash the root kernel. Once done, it should temporarily boot into TWRP recovery.
11. Finally, it should reboot into Lollipop. It may seem like it is stuck in a bootloop, but give it 5-15 minutes to load and it should finish.

Note: I already had the newest TWRP recovery image integrated with Nexus Root Toolkit, so I did not get a prompt to download it (step 9) during this process.

Root & Recovery
If you want your Nexus 7 rooted with recovery follow these steps. You can also just have it rooted if you don't want recovery. And if you just want to make a full backup (Nandroid) without recovery, you can actually perform a temp recovery:

1. Connect the Nexus 7 via USB to your computer.
2. Click "OK" when you see the RSA fingerprint on your tablet.
3. Open Nexus Root Toolkit.
4. Click on the "Launch" button.
5. Select the "Boot (Temporary)" radio button under "Boot/Flash Image".
6. Click on the "Recovery" button.
7. Select "TWRP". This should start an automatic download. If it does not work, it may give a link to download it. If it just wants you to browse to a folder that has it (as I already had it before trying this), you can download the newest, official, working version of it from here.
8. The tablet should then reboot into TWRP where you can make a backup or whatnot.

Note: If you already have the TWRP recovery image for step 7, then you can select "Manual" and browse for it instead.

If you want to root and add a recovery (or just root) follow these steps:

1. If you do not already have the free BusyBox and SuperUser apps downloaded, you can save a little time by downloading them now. (You cannot use them until you are rooted).
2. Connect the Nexus 7 via USB to your computer.
3. Click "OK" when you see the RSA fingerprint on your tablet.
4. Open Nexus Root Toolkit.
5. Check off "Custom Recovery" under "Root" if you want to add root and recovery.
6. Click the "Root" button.
7. Click "OK".
8. The Nexus Root Toolkit will then check for the root boot image. If not present, it will try to automatically download it. If it cannot, choose to download manually and it will provide a link to download from. A message to browse for the boot image will already have popped up. Browse for the downloaded root boot image and select it. Then click "OK" to proceed. The root boot image will merge into Nexus Root Toolkit.
9. The root kernel will now try to download. If it cannot, you will go through the same additional steps above required if you cannot download it automatically.
10. The Nexus Root Toolkit may also try to download TWRP recovery, and will also require the additional steps for the root boot image if it is unsuccessful.
11. The Nexus 7 should then turn off and go into bootloader as it tries to flash the rooted boot image. It will boot up again, but leave it alone. The tablet will turn off again and go into bootloader as it tries to flash the root kernel. The turn off and boot off process will likely happen once more to place TWRP recovery permanently. Once done, it should temporarily boot into TWRP recovery.
12. When you are back in Lollipop, Nexus Root Toolkit should tell you to get the SuperUser and BusyBox apps.
13. Open the SuperUser app.
14. Go to "Settings".
15. Check off "Enable Superuser".
16. Ensure to select "[Prompt]" or "[Grant]" under "Default access". "[Grant]" just skips asking you for superuser permissions when accessing an app.
17. Open the BusyBox app. If you selected "[Prompt]" in SuperUser, you will get a prompt to give superuser permissions to BusyBox.
18. It should give you some message about buying it, close it.
19. Click "Install".
20. Less than a minute later you should get a successful message.

Note: I had the tablet hang while trying to flash the root kernel during step 9. If it takes more than 5 minutes at this stage, then the procedure is stuck. To fix this, I rebooted the tablet then restarted the process, which then succeeded.

Obviously, the steps for the TWRP recovery won't be applicable to those who only chose to root the tablet. And you can delete the image files you downloaded once they have been integrated with Nexus Root Toolkit. To be safe, I would wait until the entire process is done.

Steps for Images Unsuccessfully Downloading
Reading those additional steps should be unnecessary as everything is meant to be automated. But for some reason my downloads would finish almost instantaneously [it should take some time] and then have a hash mismatch.

I partially blame my computer for this as it always has this problem with Nexus Root Toolkit for anything, including updating itself! Thankfully, it did download the factory Lollipop image without an issue.

Have Fun Nexus 7 (2012) Users!
I hope this helps anyone who find themselves in the same situation I was in. While there are a lot of steps, none are difficult to accomplish. So enjoy Lollipop, root status, and a custom recovery (if you went through everything like I did). I know I am!