firmware
embedded software / hardware control code
Noun
This term describes the bridge between hardware and software, referring to code that is embedded directly into a device's non-volatile memory. It is characterized by its persistence, remaining intact even when the device is powered off, unlike volatile RAM. Because it is an uncountable mass noun, it does not have a plural form. To refer to individual versions or specific instances of the code, users must employ partitive constructions such as a piece of firmware or a firmware update.