[SeaBIOS] Use SeaBIOS as UEFI CSM

[Kevin O'Connor]

On Wed, Oct 31, 2018 at 07:56:26AM +0100, Paul Menzel wrote:
> Dear SeaBIOS folks,
> 
> 
> Colleagues from another institute have the problem, that the PC vendors
> started to remove the CSM (legacy BIOS) option from their UEFI firmware. A
> lot of organizations still use the CSM (legcacy BIOS) option to deploy their
> systems.
> 
> I’d like to recommend SeaBIOS to them, but I only found instruction for
> doing that with OVMF [1].
> 
> Do you know of a how-to for UEFI firmware, which is shipped on hardware?
> From that iPXE should be started.

To the best of my knowledge, it's not possible to add a CSM to an
existing UEFI implementation at run-time.  As far as I understand it,
the CSM capability must be compiled into it.

-Kevin