Date: Thu, 4 Jan 2024 20:30:52 +0100
From: Alex <alex@blueselene.com>
To: ~alpine/users@lists.alpinelinux.org
Cc: Timo =?UTF-8?B?VGVyw6Rz?= <timo.teras@iki.fi>
Subject: GRUB 2.12 hell on x86_64
Message-ID: <20240104203052.36f29d01@blueselene.com>
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If you're unlucky like me and, after the GRUB 2.12 upgrade in Edge, you
had a non-working GRUB, read on:

So, if after an upgrade of GRUB, you boot the computer only to find
some text saying "Welcome to GRUB!" flash on the screen and an instant
reboot into the UEFI firmware settings, congratulations, your GRUB
installation is broken! Hopefully you have an install of
SystemRescue handy for this one.

Insert your CD/DVD/USB drive with SystemRescue and boot it. We're
going to reinstall GRUB.

Once on SystemRescue, open a terminal (if using a GUI) and run
"mountall". This script mounts all drives on the system and also
bind-mounts SystemRescue's /dev, /proc and /sys into the filesystem of
your drives if it finds them on the drives[1]. This is a necessary
step, so make sure you mount the drives using "mountall"=C2=B7.

Next, chroot into your EXT4 (or whatever filesystem you use) partition.
Once there, run "mount -a". This will use your /etc/fstab (on your
drive) to mount the rest of your filesystems on the chroot, most
importantly your boot partition.

To reinstall GRUB, run "grub-install --efi-directory=3D/boot/ --no-nvram
--disable-shim-lock" in the chroot. --disable-shim-lock is necessary,
otherwise GRUB will appear to work, but if you boot into Alpine Linux
it will complain about missing "grub_is_shim_lock_enabled" symbols and
fail. This I fixed thanks to [2]. Next, you'll want to copy the
grubx64.efi file it generates into the alpine and boot folders (for
this last one rename it to bootx64.efi). Run "apk fix grub" so that APK
regenerates the GRUB configuration just in case. Reboot and you should
have a working GRUB once again! At least I did.

CCing Timo Ter=C3=A4s, maintainer of GRUB on Alpine, since this should've
been handled by APK automatically IMO, without requiring manual
intervention like this.

[1]: https://www.system-rescue.org/scripts/mountall/
[2]:
https://github.com/NixOS/nixpkgs/issues/243026#issuecomment-1644078833

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