Re: UEFI grub install fails

[Steve McIntyre <steve@einval.com>]

mrmazda@earthlink.net wrote:
>
>I'm coming up short finding the authority on this, but I'm pretty sure there is no
>such thing as booting from an ESP that isn't on a GPT-partitioned disk, with
>correct type assigned. I think the ESP type is technically at least a 4byte value
>not supported by MBR disks, which are limited to 2byte types. The ESP also has a
>unique UUID type c12a7328-f81f-11d2-ba4b-00a0c93ec93b that has no place in an MBR
>table.

This is a common misconception, I'm afraid. While GPT is *preferred*
for UEFI and better in a number of important ways, the UEFI spec also
requires that implementations support MBR-partitioned disks for the
ESP. See [1]:

  "If an MBR partition has an OSType field of 0xEF (i.e., UEFI System
   Partition), then the firmware must add the UEFI System Partition
   GUID to the handle for the MBR partition using
   InstallProtocolInterface() "

While UEFI implementations can be buggy, I don't think I've seen one
yet that doesn't cope with this section.

[1] https://uefi.org/specs/UEFI/2.10/05_GUID_Partition_Table_Format.html#lba-0-format

-- 
Steve McIntyre, Cambridge, UK.                                steve@einval.com
Can't keep my eyes from the circling sky,
Tongue-tied & twisted, Just an earth-bound misfit, I...