Setting Grub boot option to 'Serial' by default?

Hi,

I am running VyOS 1.3-rolling-201912310217 on bare metal hardware.
I think the installer used to have an option to select wether you wanted to use KVM / Serial or USB as the default boot option, but it doesn’t seem to do it anymore?

Is there a way of changing the Grub default boot option (without editing files manually)?

Thanks,

nick.