Hacking Question about Firmware, Kernel and Loader.

[tkg21]

So, I was at work today, and we started a chat about the definitions of each.
Basically, I concluded the following, in dummy language:

• Firmware: It's the base code that manages the basic functionality of the hardware.
• Kernel: It's the base code that runs the OS of the flashcart.
• Loader: It's the base code that manages the loading of the games.

Can someone tell me if this is correct or semi-correct or not?
Also, wich carts do you know that actually has an firmware update? I guess M3i had Firmwares updates. Also, it had a kernel and two native loaders... right?