FF4 SNES SRM Checksum

I think you can break when addresses get read or written (aswell as executed). SRAM should be at $700000 so a breakpoint for write in that range should give you the save routine.

For a SNES memory map see this link:
https://en.wikibooks.org/wiki/Super_NES_..._map#LoROM

I found the checksum routine by having a read breakpoint for $7007FE.

I think the whole save slot is copied as a big chunk from WRAM though so I'm guessing $41 would be shadowed into the save slot? Then again you said you tested the whole SRAM file, so it's probably not there, I'm confused to how this might work.

Save routine is a good starting point though, good idea.