How does dual-slot mode *technically* work?

Game card reader for DS & DS Lite console replacement ds gameboy slot It won't read ds or gameboy games, so I assumed it just had some damaged pins Nov 3, 2018 by Buckets G the top card slot wont read the ds ds slot The Bright Side: The Nintendo DS wasn't 100% Game Boy Advance compatible – it didn't support multiplayer nor did it work with 8-bit Game Boy

ds lite gba slot Insert your Game Boy Advance cartridge on the bottom slot of your DS This is labeled for you next to the slot as Slot-2