Booting in text mode under GRUB2/EFI

[Udo Steinberg]

[ Please CC: me as I'm not subscribed to the list ]

Hi,

I'm trying to load a multiboot2-compliant OS kernel using GRUB2-1.99 on a UEFI
machine in 80x25 text mode. However, I'm getting the following error message:

        "OS requires a console but none is available"

The kernel includes the MULTIBOOT_HEADER_TAG_CONSOLE_FLAGS tag in the
multiboot header with console flags set to
        MULTIBOOT_CONSOLE_FLAGS_CONSOLE_REQUIRED |
        MULTIBOOT_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED.

The kernel does NOT include a MULTIBOOT_HEADER_TAG_FRAMEBUFFER tag, because
a graphical console is not desired.

The relevant code in grub-core/loader/multiboot.c that causes load failure is:

grub_err_t
grub_multiboot_set_console (int console_type, int accepted_consoles,
                            int width, int height, int depth,
                            int console_req)
{
  console_required = console_req;
  if (!(accepted_consoles 
        & (GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER
           | (GRUB_MACHINE_HAS_VGA_TEXT ? GRUB_MULTIBOOT_CONSOLE_EGA_TEXT : 
0))))
  ...
}

Because GRUB_MACHINE_HAS_VGA_TEXT is not set for an EFI platform in
include/grub/multiboot.h, this causes the only available console
GRUB_MULTIBOOT_CONSOLE_EGA_TEXT to be removed from accepted_consoles.

So my question:
Is 80x25 text mode not supported with GRUB2 on the EFI platform? Otherwise,
how do I convince GRUB2 to boot the kernel in text mode?

Cheers,

        - Udo

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