1. Delete rxTools folder (and rxTools.dat, firmware.bin) on SD root
2. Copy new rxTools folder to SD root
3. (O3DS) Copy firm folder (generated by cdn_firm.py) to SD://rxTools/
(N3DS) Rename CakesFW's N3DS firmware.bin into 0004013820000002.bin and then copy it to SD://rxTools/firm/
Done.