Since upgrading from 1.1.8 to 1.2.0-rc6, the set system console speed command doesn't seem to have an effect on the serial console port. I had the baud rate set to 115200 before upgrading and had to change it back down to 9600 on my serial client after upgrading. Even though the VyOS box is still configured for 115200, the ttyS0 isn't getting configured for 115200. Manually setting the speed to 9600 and back to 115200 doesn't work either. See below commands.
vyos@edge01:~$ show system image The system currently has the following image(s) installed: 1: 1.2.0-rc6 (default boot) (running image) 2: 1.1.8 vyos@edge01:~$ show configuration commands | grep 'system console' set system console device ttyS0 speed '115200' vyos@edge01:~$ tty /dev/ttyS0 vyos@edge01:~$ stty -F /dev/ttyS0 speed 9600 baud; line = 0; -brkint ixoff -imaxbel iutf8 -iexten vyos@edge01:~$ configure [edit] vyos@edge01# set system console device ttyS0 speed 9600 [edit] vyos@edge01# commit [edit] vyos@edge01# set system console device ttyS0 speed 115200 [edit] vyos@edge01# commit [edit] vyos@edge01# save Saving configuration to '/config/config.boot'... Done [edit] vyos@edge01# exit exit vyos@edge01:~$ stty -F /dev/ttyS0 speed 9600 baud; line = 0; -brkint ixoff -imaxbel iutf8 -iexten