The amplifier is the only device I have plugged into the Pi, and??I did follow the instructions at the bottom of the wiki for assigning the link to the USB serial port (assigning ttyUSB_AMP by VID, PID, and SN).? I also just tried your method and I'm still getting the empty payload issue. And I'm using the ?built-in USB port (which does enumerate to an FTDI serial port), and not the "Port" connector which has the "remoting USF" serial interface.
This is a version 1 amplifier, but it does have the latest firmware.? I've tried setting the "SPEProtocolV1" to both false and true, though I think true is the correct setting.
Scott
Scott - W5NJK