Hi,
I have two NDS's
1. DSI v1.4.3E
2. DS XL v1.4E
I also have three R4 cards. Two with mario on the front and one with R4 SDHC on it. The two Mario ones, as far as I can tell are identical.
Both DS's were working with their R4 Cards (Mario ones) but my daughters managed to loose on SD...