After a discussion on IRC, I tried doing the installation in expert
mode and forcing installation of grub onto the removable media path:
https://wiki.debian.org/UEFI#Force_grub-efi_installation_to_the_removable_media_path
The machine successfully booted after the installation completed.
My understanding from IRC is that installing Debian's grub onto the
removable media path is _technically_ wrong, but it is what Windows
does and various firmwares out there are broken without it. Doing this,
however, means clobbering any other OS's UEFI bootloader that was
previously installed there.
Because every BIOS has a different interface for fixing this kind of
thing, it's not very nice for users to have to fix a non-bootable fresh
install. If we can *reliably* detect that there's no other OS installed
during the grub installation.. I'd vote for just going ahead and
installing onto the removable media path by default in that scenario.
I don't have any suggestions for what to do in the case of someone
installing onto a machine that is intending to dual-boot Debian with
another OS. It's been a decades since I've dealt with dual-booting x86
machines.
On Thu, Mar 30 2023 at 03:40:00 AM -04:00:00, Andres Salomon
<dilin...@queued.net> wrote:
Oh duh, the nvram is on the board itself, not on the disk drive.
Okay, that makes more sense. The machine itself came with windows,
and then I had a different drive in it with Debian on it. Originally
legacy mode, at some point I switched to EFI and used both
shimx64.efi and grubx64.efi at alternative points in the BIOS. So
that was added by me in the BIOS, not d-i!
And then I installed this drive, which had Mint on it, and I added an
entry in the BIOS to boot it.
