I want to system transfer from my old 3DS to my New 3DS, but in case anything goes wrong I still want to be able to transfer back to an old 3DS, but I would be blocked off from doing that after transferring to the New one because you can't transfer from New to Old. So I formulated this strategy:
- NAND Backup console A and console B (console B is the new 3DS)
- Perform a system transfer from console A to console B (PC based so I can restore non-legitimate titles with FakeTik)
- Clone the SD card contents of console A to console B's SD card
- After transfer is complete, NAND restore console A
- before connecting console A to the internet, use godmode9 to remove the NNID on console A to prevent any issues with that