Amazon is already locking down the fire stick. A few years ago you could easily modify the software via adb, deactivate the updater, uninstall the menu. In the meantime they made it much harder, luckily I modified mine in time.

I remember that Gentoo recently introduced binary packages, however I didn’t really look into it, as I changed away from Gentoo. (Looking at you Spidermonkey, llvm etc.)