Bob -
You hadn't indicated if you've been able to telnet into the QMX. I'm concerned because there might be a problem with the MCU (the processor chip) - that controls everything. It's encouraging that the QMX accepted the firmware, but the inability to do poweroff could indicate a problem. If you can telnet into it then there are some diagnostics that might help. Unfortunately I can't really think of where you can go from here. Measuring the 3.3v and 5v bus voltages would at least let you know if the system has the proper voltage levels, but I've read of instances where some builders have made mistakes when doing probing and done even more damage - and I don't konw exactly where to measure those on the board. I think you're going to need the help of someone who knows more about this than I do.
Sorry,
John KI3J
