I've read this can be done as long as the card is formatted in fat32 however I couldn't find reference if they were using a modded or un-modded console. If someone is using a 3DS XL with a 64 GB card let me know. My GF is against hacking so she wouldn't be interested in a bigger SD card if it required so.
EDIT: She will be installing games from the eShop channel.
EDIT: She will be installing games from the eShop channel.