Nightcast, a member of the Krystal Archive Discord server, has been slowly working on a mod for Star Fox Adventures to get Krystal playable, the Holy Grail of Star Fox mods for a long time! He's managed to put Krystal in several places she wasn't supposed to be, with backpack and staff, which is more than what the previous ActionReplay codes could do.
He's still blocked by some complexities related to how the files are stored and manipulated in the game data. Something about being able to put the Krystal information in the right place in such a way that nothing crashes. But rest assured, as soon as he can get it working, we'll do a deep dive of it.
On that note, if there's anyone out there with experience deconstructing games or reverse engineering data formats, Nightcast would love some assistance. Comment below or email me if you want to help out.