not working well on freebsd

[bkw777]

Don't know what the issue is yet but it basically only starts to work then gets stuck on freebsd.
Maybe timing.

[bkw777]

It's some problem with the tty blocking, not timing. After getting one successful transaction like the status command, we can't send again. A logic analyser shows that the TX line doesn't change. But do a com_close and then com_open and the tty immediately both sends and receives stuff that was blocked up previously.