I used that guide when trying to do it. I made sure I used the N3DS one.https://gbatemp.net/threads/release-agb_firm-signature-patcher-gba-rom-converter.390313/
Well I tried this on both my emunand and sysnand, and it seemed to work.
Make sure to get the correct one (depending on whether you're on an o3DS or n3DS).
I've deleted it before, and I've overwrited it before, and I used Pasta when installing it to the sysnand.Pretty sure you need to delete it from your emuNAND and overwrite it in your emuNAND as well. Doing it to the sysNAND is usually only works for PastaCFW and other CFWs that patch the system.
