Comment 26 for bug 1778848

On Tue, Jul 17, 2018 at 07:15:06PM -0000, Phillip Susi wrote:
> On 07/02/2018 12:51 PM, Steve Langasek wrote:
> > On Mon, Jul 02, 2018 at 12:14:40AM -0000, Phillip Susi wrote:
> >> Why would you want to install grub-efi if you can't update the EFI boot
> >> catalog? Without that, it can't be booted in EFI mode.
> > Because with shim's 'fallback' implementation, a system that could not
> > update the boot catalog in nvram because it was not booted under UEFI
> > initially still stands a chance of auto-configuring itself to be able to
> > boot Ubuntu, via selecting the disk for boot from the firmware boot
> > selector.

> You mean we are now installing a "removable media" boot loader in
> EFI/BOOT that chainloads the one in EFI/Ubuntu?

The "removable media" bootloader does not chainload the one in EFI\Ubuntu;
it chainloads fbx64.efi, whose sole function is to (re)populate the nvram
boot settings from the set of BOOT.CSV files it discovers on disk.

https://github.com/rhboot/shim/blob/master/README.fallback

So even if the we cannot populate nvram at install time (e.g. because the
system is not booted in EFI mode at that point), it is useful to initialize
and populate an ESP for future EFI compatibility.

--
Steve Langasek Give me a lever long enough and a Free OS
Debian Developer to set it on, and I can move the world.
Ubuntu Developer https://www.debian.org/
<email address hidden> <email address hidden>