The first thing I did when I received the 3DS is to backup the SD card, to format it with guiformat and to put back the files.
[1:] SYSNAND CTRNAND, -> yes it exists
[2:] SYSNAND TWLN -> no
[3:] SYSNAND TWLP -> no
SYSNAND CTRNAND contain normal folders (data, dbs, private, ro, rw…) -> yes...