It's been a few years since I did anything code-wise on the Axo but from what I remember, I used the patch loader program as a frame and told it to look at the knob for the patch change. In the axo block, I think I told the knob to count 0-15 or something.
If you are really interested I wouldn't mind sharing the whole sd disc. If you do not have the Thonk! topper you may need to do some tweaking. No original code was used, just the stuff in the library. I know the last patch (midi pass+fx) I got from @heatseekerrr and made a few slight mods.