Re: Possible to boot DOS from UEFI grub?

[Jeff Sadowski]

your right I must have been in the MBR version of grub. I tried it
this morning and it was not working.

On Thu, Feb 28, 2019 at 4:54 PM Steve <address@hidden> wrote:
>
> chainloader (hd2)+1
>
> This does not work if you have booted via UEFI to grub2.
> It only works if you have MBR-booted to grub2,
>
>  If you have UEFI-booted then
> chainloader (hd2)+1
> will always give the error:
> error: invalid EFI file path.
>
>
> On Thu, 28 Feb 2019 at 23:38, Jeff Sadowski <address@hidden> wrote:
>>
>> 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?
>> >>
>> >> _______________________________________________
>> >> Help-grub mailing list
>> >> address@hidden
>> >> https://lists.gnu.org/mailman/listinfo/help-grub