Going back to the debug question...
So I just telnet into the empeg over ethernet to run/debug there when needed. stdout/stderr/stdin are all directed to the telnet session when running code such as this. The serial port has to be opened manually: /dev/ttyS1
So, in my Arduino code, there is a place in the code that reads input from the serial port connected to the BlueGiga chip. In addition to processing those characters, it also echoes those characters to the Arduino's debug/monitor serial port. And anything I type into the debug/monitor serial port, conversely, is echoed to the serial port connected to the BlueGiga chip, so that I can issue commands directly to test them out.
The corresponding version of that for coding on the empeg itself would be that any characters received from /dev/ttyS1 would be echoed to ... what? dev/tty<something else>?