Once you get the module, a fellow named luteijn wrote a script to set up a one shot bash prompt on the GP2X waiting for a connection (the script must be run each time you want to connect, because disconnecting kills the bash session) while the menu runs [bash script]. Then just drop the script and module on an SD card in the same directory and run the script from the utility menu of the GP2X. It will then be ready to receive connections. Once the g_serial module is loaded and working you can’t use the GP2X’s USB storage device emulation at the same time, so I came up with unbash.gpu:
unbash.gpu #!/bin/sh rmmod g_serial cd /usr/gp2x exec ./gp2xmenu > /dev/null 2>&1
On the client side, you need to have the usbserial and cdc_acm modules loaded (both found in the USB section of the Kernel menu). If you get this right, /dev/ttyACM0 should show up, which is your tty -> USB -> GP2X device.
Once that’s done right you have to setup minicom. Run minicom -s so that you go into setup before minicom initializes. Go into ‘Serial port setup’ and change the Serial Device to /dev/ttyACM0, and hit F to turn off Hardware Flow Control. Exit that menu and go into ‘Modem and dialing’, and hit A and clear the entire ‘Init String’ (it’s useless for this purpose). Then you should be good to go. Save the setup for easy reuse and then exit the menu and you should be greeted by a bash# prompt on your GP2X.
Screen has subsequently been ported to the GP2X. You’ll probably want to add the ‘-m’ switch when running minicom, as this makes it use ALT-key instead of CTRL-A-key for accessing it’s menus. Using ‘-m’ it won’t overlap with screen’s CTRL-A commands.