Hi
I loaded midi's from floppy to my SD Card via the following
Press
SD Load Button next
SD Tools Button ( top left)next
SD SOUND Tools Button (bottom right) next
Copy from disk.

It worked for me.

best wishes
Rikki
forgot to mention midifiles play via "Sound Play" in the SD menu.
_________________________
best wishes
Rikki 🧸

Korg PA5X 88 note
SX900
Band in a Box 2022