Installing 1.4.0-rc1 onto [[ https://www.pcengines.ch/apu6b4.htm | PCEngines APU6b4 ]] with onboard drive causes the following messages:
```
GRUB loading.
Welcome to GRUB!
```
No further comms on that serial port are observed, even after machine boots.
I can eventually log in via an ssh connection over ethernet, but there is now no path for rescuing this router.
Vyos config-mode displays:
```
show system console
device ttyS0 {
speed 115200
}
```
Permissions on ttys:
```
ls -l /dev/ttyS*
crw--w---- 1 root tty 4, 64 Jan 8 16:46 /dev/ttyS0
crw-rw---- 1 root dialout 4, 65 Jan 8 16:17 /dev/ttyS1
crw-rw---- 1 root dialout 4, 66 Jan 8 16:17 /dev/ttyS2
crw-rw---- 1 root dialout 4, 67 Jan 8 16:17 /dev/ttyS3
```