Re: Possible to boot DOS from UEFI grub?

[Jeff Sadowski]

Interesting someone suggested chain-loading
the MBR version of the boot loader and boot DOS from there.
Which worked.

I did
chainloader (hd2)+1

Then I was able to use the DOS menuentry to boot DOS.

On Thu, Feb 28, 2019 at 5:59 PM Steve <address@hidden> wrote:
>
> 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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