---HOW TO UNBAN URSELF THX NINTENDO LOLOLOL BEST TUTORIAL 2019---
1) get a non-banned 3ds
2) dump the LocalFriendCodeSeed_B with decrypt 9 by opening d9 > sysnand options (or emunand if its the case) > system file dump > dump LocalFriendCodeSeed_B
put it inside the decrypt9 folder of your sd root
3) in your 3ds follow the same steps but use the system file inject option instead
also, make a dump of your own LocalFriendCodeSeed_B (just in case)
4) (seems like this step can be skipped and you wont lose your friends list) once you injected the seed, go to some kind of file manager like godmode9 and delete the files inside:
nand://data/id0/sysdata/00010032/
The other depends on your region:
Japan:
nand://data/id0/sysdata/0002008D/
USA:
nand://data/id0/sysdata/00020096/
Europe/Australia:
nand://data/id0/sysdata/0002009F/
this will reset your friend list
this is how i got unbanned (games only - error 002-0102)
EDIT: wrote this in case someone still hasnt figured out how to do it