Comment 1 for bug 1743884

I've found that the offending line in /boot/grub/grub.cfg is:

terminal_output gfxterm

Prior to that, my active input and output terminals are set to "console". If I comment out that line, I can interact with the installed GRUB over both the serial and VGA consoles, just like with d-i.

I'm not sure what the right solution is. One option is to change:
  terminal_output gfxterm
    to:
  terminal_output --append gfxterm

That makes both "console" and "gfxterm" active. But, maybe it makes more sense to just not emit the "terminal_output gfxterm" under certain conditions. Does gfxterm have any effect on other UEFI-based systems?