I'm trying to transfer a screen capture from a device using the xmodem protocol.

I can do so successfully using minicom with the settings: /dev/ttyACM0 baud 38400, 8n1, no hardware or software flow control. The xmodem rx config line is /usr/bin/rx -vv -c (I had to add the -c).

However I need to do this using a bash script.

Here is what I'm trying:
stty -F /dev/ttyACM0 38400 clocal cread -crtscts cs8 -cstopb -parenb
rx -vv -c test.bmp < /dev/ttyACM0

I get a block of garbage but then the device fails, Ctrl-C will get me out.

I've read the man/info on stty, setserial, rx, minicom, and done extensive searching including checking out the source on minicom. However I don't know C. Any help would be greatly appreciated.