GNU bug report logs - #66207
Cannot boot any recent VM built with “guix system image -t qcow2”

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Message #25 received at 66207 <at> debbugs.gnu.org (full text, mbox):

From: Mathieu Othacehe <othacehe <at> gnu.org>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: Ricardo Wurmus <rekado <at> elephly.net>, 66207 <at> debbugs.gnu.org
Subject: Re: bug#66207: Cannot boot VMs with grub-efi-bootloader
Date: Sun, 01 Oct 2023 22:21:56 +0200

Hey,

Some context around that.

Before recent commits, when we were producing qcow2 or raw images,
those were MBR images with an EFI partition. If the grub-bootloader
was used, then Grub was installed both in the post-MBR gap
and in the EFI partition. This means that a single image could be booted
with or without the qemu -bios option, i.e both in BIOS legacy
or in EFI mode.

Commit d57cab764122af69d52d8cc9c843456044e5d7bc changed the default
behaviour and the produced images were by default MBR images, without
EFI partitions.

I changed that with e5ed1712da049b1c3dcf01e0a7e02e48a8aff012 and
dfaeaae9c7e7283b99ad10aef3e61402e9820bc7 which introduced a new image
type called mbr-hybrid-raw, which is now the default image type,
restoring the previous behaviour.

Now it looks to me that what Ricardo is observing is not linked to any
of the changes mentioned above.  When using the grub-efi-bootloader,
Grub is never installed in the post-MBR gap. This was already the case
in 1.4.0 and is still true. Those images cannot be booted without the
qemu -bios option unless I'm mistaken.

Hope it helps,

Mathieu

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