Installing a fresh version of VyOS in VMWare ESXi for testing purposes w/ RAID1 support ended with an installation that can't boot.
There was a previous task T289 mentioning a similar problem but this was a higher layer issue, not GRUB itself.
GRUB replys by:
error: disk 'md/0' not found. error: you need to load the kernel first
Installing software RAID with defaults went down smoothly.