Nokia had Linux on their smartphone until Microsoft bought them and stopped everything, they even shut down the app store. The OS was called MeeGo. Part of the Nokia team however started their own company called Jolla and still produce smartphones running Linux, they call their OS Sailfish. (ignoring the fact that Android also uses the Linux kernel). The problem with alternative phone OS:es is that in the country I l…
There is a fork called Maemo Leste [0][1] that is actually still around and updated. I have it running on a droid 4, and it works pretty well. The UI is still the same Hildon UI. Definitely a fun OS and device to play around with, and interesting in that it's the only mobile OS I'm aware of that is running Devaun.
[0] https://maemo-leste.github.io/
[1] Technically a fork of Maemo, the predecessor to MeeGo.