@cinimodev @zak For me, there's a blurry line here. On mobile, the firmware, i.e. rom is integrated with the Software - OS and above.
This would include critical OS updates that could be done manually on a rooted/jailbroken phone e.g. rewriting the kernel file, to bootloader and SoC drivers (closer to firmware defined as program code living on mobo nonvolatile storage not part of the hard drive).
The tendency towards FLOSS platforms allows for easier modding, but mobile tends the other way.