Nintendo 3DS Flash Cards - R4 3DS and R4i SDHC upgrade
Crown3DS is the first of many R4 3DS flash cards that can play 3DS roms. Before this DSi and N3DS Compatible flash cartridges like R4i Gold 3DS, SuperCard DSTWO or AceKard 3 tcould run DSi and NDS rom files, Homebrew, DivX, MP3s and Emulators on the new Nintendo 3DS, but could not run backup copies of the new 3D ROM games. Read more about Nintendo 3DS Flash Cards and Buy Crown3DS at the Official R4 Shop.com
Nintendo DS Flash Cards
NDS ROM Backup Tools -- Want to play Nintendo DS Roms on the NDS for free? If YES - You don't even need to chip your DS - what you need is one of the DS Flash Cards / DS microSD Memory Card Adapters: G6DS, R4DS, M3DS Real and others compared. Read reviews here: G6DS Real, R4 DS Revolution Review, M3 DS Simply, M3 DS Real, CycloDS Evolution DS-X 16G Mk5
NinjaDS, Ultra Flash Pass EX and DS Linker.