GPD MicroPC - installing Ubuntu Mate

Trying to install Ubuntu Mate's official version for the GPD MicroPC from a USB drive but on boot it keeps defaulting to the grub menu, has anyone encountered this issue before?

Can we talk bios settings?
My gpd micro pc boots & install from mate 20 iso.
However it fails to install a boot partition (rest is encrypted). Uefi bios
Strange thing is that it takes to dd if of the USB key again to be able to boot... (and I get access to my installed system -but not installed kernel...-)

Reproductible

Probably a security feature and not a bug, which allows /boot on external key

Gonna RTFM