Heck. I found a couple old R4 cards. ... Ones really really old, the other is newer and is meant to work on 3dses but... I think it's defunct because the site (apparently a newer site) doesn't seem to list this R4 card any more... So it might basically be dead, and it doesn't work on my dslite now either.
maple classic™ 
@Nine what happens? does it get stuck on "loading"? might need kernel files in the microsd, they won't boot without those
mine once had to had its firmware reflashed to keep working on a 3ds, and that could only be done through a regular ds
@squirrel
Nah, on my dslite I get the red "error" slowing a micro SD, and on my 3ds it shows a black screen with "an error has occurred" . I think either I've flashed it with the wrong firmware or its blocked
@Nine mm. could be a wrong firmware, yeah :( i'm sorry
it's probably salvageable but i wouldn't know how
