Lerxst,
It's not the firmware that you load via the RS232 socket and PC. This is the actual rom drive driver software which is loaded via a particular sequence of open/close draw, on/off/stop type stuff from a CD.

Definitely get in touch with M for this as you need to do it properly. FWIW, when I had a 596 I did this a couple of times.

Rgds

Nick

Rgds,
Nick