Serial console on 8.x doesn't work properly
The serial console on 8.x based versions doesn't work properly. The boot messages show up, and if the system panics you get a debug prompt, but output stops at "Bootup complete" and you cannot interact with the system at all after it boots up.
Update ttys serial lines. Resolves #165
To prevent collisions with the sio(4) driver, the uart(4) driver
uses different names for its device nodes. This means the
onboard serial port will now most likely be called "ttyu0"
instead of "ttyd0". You may need to reconfigure applications to
use the new device names.