@steelman @fsf @fsfe “Software is the operational part of a device that can be copied and changed in a computer; hardware is the operational part that can't be. This is the right way to make the distinction because it relates to the practical consequences. […] firmware that is delivered inside the device and can't be changed is software by nature, but we can treat it as if it were a circuit.” ― https://www.gnu.org/philosophy/free-hardware-designs.en.html
That specific piece of code on PROM is hardware and no longer a software.