I've updated the Reboot.ms' Autofirm in order to apply old 10.4 Native_firm also to any 11.0 - 11.2 NAND dump (old3DS/N3DS compatible)
This was useful to downgrade from 11.2 to 9.2 before the release of fasthax+safehax.
This is yet a valid method to downgrade, but not the easiest one.
LINK...