How to reproduce the issue:
1. Start a FreeBSD VM with QEMU >= 2.11.0, appending `-serial pty` to its command line.
2. On the VM, run `minicom -H -D /dev/cuauX`
3. On the host, run `minicom -H -D /dev/pts/Y`
4. On the host, type something and hit ENTER
The minicom running on the VM will then show an extra 00 char after 0d.