Specify which graphics adaptor GRUB should use

I have a motherboard with a simple 2D onboard graphics accelerator (I believe it sits on the PCIe bus). I have also installed a separate PCIe Nvida GeForce card which I would prefer to use exclusively. The onboard device only has a single VGA out – this is what GRUB defaults to using. I would like to not have to use the VGA interface at all. Is there a way to force GRUB to be displayed through the Nvidia adaptor?

This is particularly painful as I have to enter in the LUCKS HDD password over VGA rather than HDMI. Once booted Ubuntu will switch to the Nvidia adaptor