Hi Michael, I've found the firmware you are looking for, but I cannot find the source (where I got it from). Someone in this group (I believe Richard) posted the link a while ago and I've tried using the firmware. As a result though, I still cannot hear any output even though it does play back SACDs. I may be doing something wrong, but I cannot figure out what it is. You're welcome to try this firmware and please let me know if you were successful. Just use it like you would a normal firmware update (be cautious and don't interrupt).
I've posted it to your to your email address.I hope it works for you. Possum