There are some Android devices which other people have already built and installed Firefox OS for.
If you have a Galaxy S2 and Nexus 5 it may be a bit easier to port Firefox OS - however, there is always the risk of bricking your device and making it useless.
Please also be aware that not all features of Firefox OS may work correctly on a ported build. If you are curious to know more, you may find information on these sites:
You can also try the Firefox OS by running the simulator in your Firefox browser. Please check the following article for instructions:
If you are an advanced user and would like to learn more information about manually porting Firefox OS to your specific device, you can go to MDN (Mozilla Developer Network):
We hope you find this information helpful. Please let us know if you have any other questions.