I'm trying to understand the firmware on the Raspberry Pi.
My understanding was that firmware related only to persistent software not influenced by anything which is on any particular SD card, but it seems that's not the case on the pi and that firmware is also being used to describe low level boot states that are loaded from the SD card.
I would like to know are there any user upgradable firmware settings that do persist without reference to any particular SD cards contents? If so, which ones (in general terms)?