Ok, this might be too much safety, but i wanna make sure you're safe. First dump localFriendCodeSeed_B from the unbanned 3ds, and put it in the files9 folder of the banned 3ds. The, not sure if i can link it here, but find an nnidsave.bin. Theres a youtube video called how to unban 002-0102. Use the file in the descryption. Put that file in files9 on the banned 3ds as well. Last, dump the secureinfo_A from the banned 3ds, and open it in a hex editor. At the bottom of the hexes should be your console id. Change the numbers around however you want, just make sure the first 2 letters, either qw or cw, stay the same. lastly, just restore all 3 files using decrypt9.