Well, first problem was corruprted file reads via Aspeqt, so switched to APE. VBMP then reported core 1.20 not present, so I recompiled it to check for (newly flashed) 1.24. I then get this:
Funnily enough, I got the same thing with FC.COM (but worked around it to get the firmware upgraded). Basically it calls the file selector with "E1:", and tried to read from the console. I press break, choose "D1:", then get what's displayed above.
...OK. I tried running it with SDX's "X" command and it works.
FlashJazzCat:
Do not "try" X command under SDX. Simply use it always