Yes, only boot.firm
You could also just use Universal-Updater to update Luma3DS (and any other homebrew) to the latest version without the need of taking the sd card out of the 3ds to your pc. Ftp is also an option (with ftpd).
Hold select on boot it'll show Luma3DS Menu it'll say what version...
"The new Nintendo Switch 2, comes with slightly bigger & brighter screen, joycons prolly the same, a %10 cpu, gpu, teraflops increase blah blah etc. and there's Switch Virtual Console (or BC) where you have to rebuy all your Switch games again, or you can just join the new Nintendo Switch Online...