Re: Possible to boot DOS from UEFI grub?

[Steve]

When you UEFI-boot, the CPU is in Long Mode and there is no BIOS support
(BIOS interrupts are not supported).

DOS works in Real Mode and uses BIOS interrupts for kbd, screen and disk
access, etc.

So there is no way you can UEFI-boot to DOS!



On Thu, 28 Feb 2019 at 22:52, Jeff Sadowski <address@hidden> wrote:

> OK I've been trying a bunch of things here but not having much luck.
>
> I am familiar with normal booting from UEFI grub and MBR versions of grub
>
> I can boot DOS from Legacy Grub with the following
>
> grub> root='hd2,msdos1'
> grub> parttool ${root} hidden-
> Setting partition type to 0x6
> grub> drivemap -s (hd0) ${root}
> grub> chainloader +1
>
> If I try this in UEFI grub
>
> grub> root='hd2,msdos1'
> grub> parttool ${root} hidden-
> Setting partition type to 0x6
> grub> drivemap -s (hd0) ${root}
> error: can't find command `drivemap'.
> grub> chainloader +1
> error: invalid EFI file path.
>
> If I try and let update-grub fix it They go away completely if I boot
> from UEFI mode.
>
> For now I have resigned to just booting everything from Legacy mode
> but would like to know if it is possible to use it from UEFI mode?
>
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