At the request of many of our readers, we've decided to write the following tutorial to teach them how to install the Ubuntu Linux operating system on the Raspberry Pi 2 single-board computer (SBC).
In the past, it was not possible to install the Ubuntu Linux operating system on the original Raspberry Pi computer, but the second-generation Raspberry Pi Model B board features an ARMv7-based BCM2709 processor, allowing you to run the GNU/Linux distribution.
Some members of the Ubuntu Linux community managed to modify an official Ubuntu 14.04 LTS (Trusty Tahr) image, upgrade its original Linux 3.13 kernel to Linux kernel 3.18, as well as add all the necessary firmware and drivers from a third-party PPA (Personal Package Archive) to make it work on the Raspberry Pi 2 SBC.
As you might know, the Ubuntu MATE developers released a while ago a set of tools that could allow anyone to create Raspberry Pi 2 versions of any other Ubuntu flavor, including Xubuntu, Lubuntu, Ubuntu GNOME, and even Ubuntu Server and Ubuntu Desktop.
Installing Ubuntu on your Raspberry Pi 2
Now, if you want to install the Ubuntu 14.04 LTS (Trusty Tahr) operating system on your Raspberry Pi 2 device, which is the latest long-term supported version of Ubuntu Linux, you will need first to download the specially crafted Ubuntu image for Raspberry Pi 2 and save it somewhere on your Home directory.
You will then need to extract the contents of the zip file and write them on an SD card of 2GB or higher capacity using the following command, where "/dev/sdX" is the SD card, so you will need to list the attached devices to find out its exact location (e.g. /dev/sdc or /dev/sdd, depending on how many drives you might have).
At the moment, only the Xfce, LXDE and KDE are known to work, so you'll need to install the respective packages if you want a full-featured user interface, such as xubuntu-desktop, lubuntu-desktop, or Kubuntu-desktop (see the commands below). That's it, if you have any other questions, you can drop a comment.
sudo apt-get install lubuntu-desktop
sudo apt-get install kubuntu-desktop