http://tstzmgqansvqfzr3qrkehszmlhjqbpqp7pwncrzr72ohyygrnbuu26qd.onion/articles/firmware-broken-terminology
The annoying part is seems to serve as a way of hiding that it is in fact just plain software, meaning something you can modify, rewrite, audit, … albeit sometimes with the hardware putting some limits but that says more about the hardware than the software.