https://gbatemp.net/threads/new3ds-with-arm9-wont-start-with-new-128gb-exfat-micro-sd-card.428951/
Man, the SD Formatter used exFAT, not FAT32. Maybe is this. I'll try to format to FAT32, paste my backup and test again. If this dont work, i'll follow your sugestion.
Sent from a abandoned city...