This crash has been happening to me every time I use a special attack on Pokémon Omega ruby and Pokemon X or randomly while playing Smash. I replaced the 4gb SD Card
Lexar 4GB SD SDHC Memory Card SD C4 Secure Digital SDHC Class 4 for Camera NEW | eBay
SDHC Memory Card for Nintendo Wii and DSi | GameStop
Nintendo 3DS LL RED Soft japanese SD card 4GB touch pen included good condition | eBay
If you haven't swapped out your old 3DS 4GB card, it's probably a good idea to do so : r/3DS
Upgrade Storage for the New Nintendo 3DS XL 2015 - iFixit Repair Guide
How to Format SD Card for Nintendo 3DS (XL) with Freeware?
Nintendo Pink 3ds Xl With Charger & 4gb Sd Card Very Good Condition. Free Game
4GB SD Card 4 GB Digital Memory Card (Elite Pro) – A & C Games
Nintendo 3DS XL EUC Blue/Black with 4GB SD Card SPR S BKAB USZ | #1789588496