Guys, please stop being dumb about voltages, express card vs microSD etc.
Switch cartridges are UPDATEABLE. (The Lotus 3 chip inside them).
https://switchbrew.org/wiki/Lotus3
I believe that Nintendo have identified the spoofed Lotus3 checks and thus have "blocked" them on SW2, in order to weed the "mig-flash" out and render it useless, they no longer accept the cartridges with the old Lotus3 code.
I believe they are forcing an update to our SW1 Game Lotus 3 chips upon insert into the SW2....
When you insert a SW1 - do you at all notice how it updates and how fast it is?
Just saying.