bug#47889: [installer image] grub-install efi fails getting canonical path to /boot/efi on dos-formatted disk

[pelzflorian (Florian Pelz)]

Hello Bengt,

On Sat, Apr 24, 2021 at 05:24:26AM +0200, Bengt Richter wrote:
> How does that work if you want to mount an external USB disk as the target
> of your installation partitioning and formatting etc, but which may be 
> intended
> for another laptop with a different BIOS booting in a different mode than your
> installer was booted into? (Maybe plug the finished USB disk into another 
> laptop?
> USB C3.1 is fast enough if connected to a good SSD cassette).

Do we want to support such rare use cases in the default
configuration?  Currently the configuration created by the installer
assumes you want to install to the same boot mode (UEFI or “legacy”
BIOS) as was selected when booting the installer.  This means that if
your computer only supports one or the other, you have no choice.  It
does not depend on what’s on the disk.

Also, in UEFI mode, the grub-efi-bootloader from
gnu/bootloader/grub.scm would need to be copied and adapted to add the
--removable option if you want to install to a removable USB in UEFI
mode.  This is because grub-efi-bootloader otherwise writes boot
information into your BIOS’s NVRAM on the mainboard of the computer
doing the install.

Regards,
Florian