Not every update is a firmware update. But every update is a software update.
Firmware in this context is (most likely from what I can tell) 2nd stage bootloader that exists in EFI. It's pretty rarely updated. This is Package1 that they talk about here and http://switchbrew.org/index.php?title=System_Versions here. Even less if we're talking about firmware updates that burnt a fuse (bottom of this page http://switchbrew.org/index.php?title=Fuse_registers#FUSE_RE...)
So despite 11 Software updates, there has only been five firmware updates.
When we're talking about fuses odm_reserved has 256 bits to play with. Assuming that one bit is 1 fuse. Then they can do 256 firmware updates before they're in trouble.
Firmware is a pretty horribly misused term these days.
"640K ought to be enough for anybody!"
But seriously, in the 3DS world, they've been going back and forth with hackers for a long time. There are a lot of updates for that system:
http://en-americas-support.nintendo.com/app/answers/detail/a...
Any time you see "Further improvements to overall system stability and other minor adjustments have been made to enhance the user experience," it's them closing an exploit vector. That would be a lot of fuses to blow.
I wonder how many of these systems have secure enclaves and some ability to have a WORM-style hardware incrementer. The SoC version of an odometer.