Installing Ubuntu Touch on Nexus 7 (2012) now that it is no longer supported

Since yesterday I have on my Nexus 7 2012 desktop Ubuntu 14.04.3 LTS, so I think steps for reproduce this on Ubuntu Touch can be similar (or you can try desktop version).

So everything you doing on your own risk. :-)

My steps was in short this:

1. Flash Ubuntu 13.04 via Fastboot (commands in previous answer)

2. Edit file with repositories at /etc/apt/sources.list based on this examples (I choose Trusty because it is next LTS after 13.04 and I doesn't expect any problems)

   deb http://ports.ubuntu.com/ trusty main restricted
deb-src http://ports.ubuntu.com/ trusty-security main restricted

3. Make apt-get update and apt-get upgrade

4. Optional: Install SSH server with apt-get install ssh

5. Restart tablet and enjoy latest LTS version of Ubuntu :-)

Source: my today blogpost (in Czech)

Step One: Download Everything

First, grab the latest Raring daily build files for the 2012 Nexus 7:

ubuntu-13.04-preinstalled-desktop-armhf+nexus7.bootimg

ubuntu-13.04-preinstalled-desktop-armhf+nexus7.img.gz

(found here: http://old-releases.ubuntu.com/releases/raring/)

Next, grab the tools required to install these build files to your device:

1. On your computer, press Ctrl+Alt+T to start a terminal.

2. Add the Ubuntu SDK Release PPA:

   $ sudo add-apt-repository ppa:ubuntu-sdk-team/ppa

3. Update your system to use the latest packages:

   $ sudo apt-get update

   $ sudo apt-get upgrade

4. Install the ubuntu-device-flash package:

   $ sudo apt-get install ubuntu-device-flash

(found here: https://developer.ubuntu.com/en/phone/devices/installing-ubuntu-for-devices/)

Step Two: Unlock Your Device

The 2012 Nexus 7 ships with a locked bootloader meaning you must unlock it to flash different images to the device. Fortunately, this is a trivial process, and you only need to do it once.

(Warning: Unlocking the bootloader erases all data and resets the device to factory defaults. If you would rather not lose all of your precious cat pictures, back them up to your computer!)

1. Reboot your 2012 Nexus 7 into the Android boot loader. To do this, first power down the device in the normal fashion (hold down the power button, then select power off and wait a few seconds). From the off state, hold the volume down button and press the power button. Continue holding the volume down and power buttons until you see the boot loader UI.

2. Using a micro-USB cable (the one you use for charging should be fine), plug your device into any computer running Ubuntu. The device now displays the boot loader GUI, which looks like this:

3. Verify fastboot lists the device. In a terminal on Ubuntu, run:

   $ sudo fastboot devices

4. Start the bootloader unlock process:

   $ sudo fastboot oem unlock

5. Your device should now prompt you to unlock the bootloader. Follow the on-screen directions to continue. Your screen should now look like this:

6. Complete the process by rebooting:

   $ sudo fastboot reboot-bootloader

When the device reboots back into the bootloader (fastboot mode), you should see "LOCK STATE - UNLOCKED" in small red print. At this point your device is now unlocked.

(from here: https://wiki.ubuntu.com/Nexus7/Installation)

Step Three: Install Everything

1. Gunzip the *.img.gz file downloaded in Step One to extract the .raw file inside.

2. Verify once more that your device is connected via micro-USB and that fastboot lists the device by running the following in terminal:

   $ sudo fastboot devices

(If your device is not listed, ensure that the device is turned on and booted to the bootloader.)

3. Issue the following series of commands:

   $sudo fastboot erase boot

   $sudo fastboot erase userdata

   $sudo fastboot flash boot /path/to/*.bootimg

   $sudo fastboot flash userdata /path/to/unzipped/*.raw

   $sudo fastboot reboot

Step Four: Use Your Device

If everything went right, you should now have Ubuntu Desktop running on your 2012 Nexus 7! The installer will likely be buggy, but very familiar. Beware, of course, that this version of Ubuntu is no longer supported by Canonical, and you may have some difficulty finding and using the latest applications on your device. Good luck, and have fun with your newish oldish Ubuntu tablet!

You can use the manual installation instructions from https://wiki.ubuntu.com/Nexus7/Installation - the location of the files is no longer valid, but the files are still available here: http://cdimage.ubuntu.com/releases/raring/release/

The instructions boil down to these commands:

fastboot erase boot
fastboot erase userdata
fastboot flash boot /path/to/*.bootimg
fastboot flash userdata /path/to/*.img

However there seem to be other options for getting a "real" Linux on the Nexus 7 (2012) which are listed here https://github.com/Tasssadar/multirom/wiki/Grouper-Native-Desktop-Linux

Please also note that Nexus 7 (2013), Nexus 4 and Nexus 10 are supported by Ubuntu Touch, see https://developer.ubuntu.com/en/start/ubuntu-for-devices/devices/