To install PX4 firmware (for moment only the quad is available).
Connect your Erle-Brain2 to internet, open one terminal and execute the following commands:
sudo apt-get update
sudo apt-get install px4-erle-robotics
Open a terminal and type the following:
sudo apt-get purge -y px4-erle-robotics
Note: Before install PX4 package please uninstall other apm package. Please, be careful with PX4, for the moment is beta.