EFI support in the kernel

[Ken D'Ambrosio]

On 2020-01-26 07:22, Volker Wysk wrote:
> Hi
> 
> I don't have a /sys/firmware/efi directory. I think this means that the
> running kernel doesn't have (U)EFI support.

Note that I'm not a UEFI demigod, but I think you've got it backward, 
really.  UEFI is more about how your system is working than your kernel, 
itself.  By the time you're loading the kernel, everything that *needs* 
to know about UEFI has already done its job: the MBR/bootloader & BIOS.  
(Though, really, UEFI is a replacement for "BIOS", but I'm using the 
term generically.)  The nutshell is that to get your system booting 
UEFI, you have to have your BIOS thusly configured, AND do a UEFI-based 
install at installation time.  (The install used to require you to 
select UEFI from the GRUB menu at install time; I think Ubuntu may have 
enough smarts now to simply pick the default.)  But I don't see anything 
approaching an even vaguely easy way to do this retroactively: you need 
to change your disk layout (need an EFI partition), need to populate it, 
change your BIOS from "legacy" to "(U)EFI", etc.  I do not see there 
being anything but pain and suffering trying to make this happen 
post-facto.

-Ken