So i did everything as you said, but does not work. Two squares (green and grey)appeared on the top right corner but none of them worked. Afetr a few seconds a window showed up in the middle of the screen with a message and a floppy disc , but all in jap, so know idea what the problem is.
I made a PX68K folder in the internal storage, and put all the bios files and DIM files in that. I tried 0.15 and 0.14 but failed.
(My console is a Q9 not an XD)