best free software system options for beagle bone black?

https://www.beagleboard.org/boards/beaglebone-black
When the beagle bone black got on the marked I obtained one because I heard it is able to run entirely on free software. I wanted to use it for flashing libreboot on a thinkpad t400. It did not work. And I used a raspberry pi. Today what are the best options in term of free software systems for the beagle bone black? Thank you.