As of ~April 2021 the Meta/build-image-grub.sh script no longer works
for me (on Fedora 34) and fails with the following error:
/usr/sbin/grub2-install: warning: ../grub-core/partmap/msdos.c:403:
your core.img is unusually large. It won't fit in the embedding
area.
/usr/sbin/grub2-install: warning: Embedding is not possible. GRUB
can only be installed in this setup by using blocklists. However,
blocklists are UNRELIABLE and their use is discouraged..
/usr/sbin/grub2-install: error: will not proceed with blocklists.
Changing the size of the boot partition from 32 kiB to 1 MiB (2048
sectors) fixes the issue. This is also described in the following Ubuntu
grub2 bug (as well as 40 duplicates!) from 2012, which suggests the same
fix: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1059827
The Arch Linux wiki also uses 1 MiB in their BIOS/MBR examples for
parted: https://wiki.archlinux.org/title/Parted
I'm not sure why this suddenly stopped working, however I was able to
boot with an image created with this change applied.
In the GNU coreutils version of chown, ":" is a valid argument
(the command will result in a no-op), but POSIX chown does not
consider that valid.
If the user who ran build-image-*.sh was root, SUDO_UID and SUDO_GID
would not be set and, if the version of chown installed on the system
did not allow passing just a ":" as argument, the script would fail.
Let's default the value of SUDO_UID and SUDO_GID to 0 just in case.
