grub-pc versus grub-efi-amd64

Tue Sep 1 12:18:01 UTC 2020

Am Montag, den 31.08.2020, 20:57 +0200 schrieb Tom H:
> On Mon, Aug 31, 2020 at 7:02 PM Volker Wysk <post at volker-wysk.de>
> wrote:
> > Am Montag, den 31.08.2020, 14:27 +0200 schrieb Tom H:
> > > On Sat, Aug 29, 2020 at 5:31 PM Volker Wysk <post at volker-wysk.de>
> > > wrote:
> > > I installed 20.10 right after 20.04 was released on an EFI
> > > system,
> > > and I also have "grub-pc" rather than "grub-efi-amd64" installed.
> > 
> > And this isn't a packaging bug...
> 
> I don't think so. I _feel_ that it's more likely to be an apt bug.

So you *do* think that it's a bug - that grub-efi-amd64 should be
installed rather than grub-pc.

And installing grub-efi-amd64, to replace grub-pc, really really won't
break the system..? I'm hesitant...  :)

There is quite something happening when doing it:

-----snip-----
desktop ~ % apt --simulate install grub-efi-amd64
(...)
Inst grub2-common [2.04-1ubuntu26.2] (2.04-1ubuntu26.3
Ubuntu:20.04/focal-updates [amd64]) [grub-pc:amd64 ]
Remv grub-pc [2.04-1ubuntu26.2] [grub-gfxpayload-lists:amd64 grub-efi-
amd64-signed:amd64 ]
Inst grub-efi-amd64 (2.04-1ubuntu26.3 Ubuntu:20.04/focal-updates
[amd64]) [grub-gfxpayload-lists:amd64 ]
Remv grub-gfxpayload-lists [0.7] []
Inst grub-pc-bin [2.04-1ubuntu26.2] (2.04-1ubuntu26.3
Ubuntu:20.04/focal-updates [amd64]) []
Inst grub-efi-amd64-signed [1.142.4+2.04-1ubuntu26.2] (1.142.5+2.04-
1ubuntu26.3 Ubuntu:20.04/focal-updates [amd64]) []
Inst grub-efi-amd64-bin [2.04-1ubuntu26.2] (2.04-1ubuntu26.3
Ubuntu:20.04/focal-updates [amd64]) []
Inst grub-common [2.04-1ubuntu26.2] (2.04-1ubuntu26.3
Ubuntu:20.04/focal-updates [amd64])
Conf grub2-common (2.04-1ubuntu26.3 Ubuntu:20.04/focal-updates [amd64])
Conf grub-efi-amd64 (2.04-1ubuntu26.3 Ubuntu:20.04/focal-updates
[amd64])
Conf grub-pc-bin (2.04-1ubuntu26.3 Ubuntu:20.04/focal-updates [amd64])
Conf grub-efi-amd64-signed (1.142.5+2.04-1ubuntu26.3
Ubuntu:20.04/focal-updates [amd64])
Conf grub-efi-amd64-bin (2.04-1ubuntu26.3 Ubuntu:20.04/focal-updates
[amd64])
Conf grub-common (2.04-1ubuntu26.3 Ubuntu:20.04/focal-updates [amd64])
-----snip-----

> Consider the output below of "dpkg -s" for all the grub packages on
> my
> laptop (with only the relevant lines kept).
> 
> "grub-efi-amd64-signed" depends on "grub-efi-amd64 | grub-pc", which
> is the correct priority to install "grub-efi-amd64".
> 
> But
> 
> "grub-common" replaces "grub-efi-amd64 (<< 2.00-4)"
> 
> "grub-efi-amd64-bin" replaces "grub-efi-amd64 (<< 1.99-1)"
> 
> "grub2-common" replaces "grub-efi-amd64 (<< 2.02+dfsg1-7)" and breaks
> "grub-efi-amd64 (<< 2.02+dfsg1-7)"
> 
> So, even though the Replaces/Breaks versions are below the current
> "2.04-1ubuntu28", the resolver must somehow end up preferring
> "grub-pc".
> 
> Maybe...
> 
> # dpkg -s grub-common
> Replaces: grub-coreboot (<< 2.00-4), grub-efi (<< 1.99-1),
> grub-efi-amd64 (<< 2.00-4), grub-efi-ia32 (<< 2.00-4), grub-efi-ia64
> (<< 2.00-4), grub-ieee1275 (<< 2.00-4), grub-linuxbios (<<
> 1.96+20080831-1), grub-pc (<< 2.00-4), grub-yeeloong (<< 2.00-4),
> init-select
> Depends: libc6 (>= 2.28), libdevmapper1.02.1 (>= 2:1.02.36),
> libefiboot1 (>= 37), libefivar1 (>= 37), libfreetype6 (>= 2.2.1),
> libfuse2 (>= 2.8.4-1.4), liblzma5 (>= 5.1.1alpha+20120614), debconf
> (>= 0.5) | debconf-2.0, gettext-base, lsb-base (>= 3.0-6)
> 
> # dpkg -s grub-efi-amd64-bin
> Replaces: grub-common (<= 1.97~beta2-1), grub-efi-amd64 (<< 1.99-1),
> grub2 (<< 2.04-1ubuntu28)
> Depends: grub-common (= 2.04-1ubuntu28)
> 
> # dpkg -s grub-efi-amd64-signed
> Depends: grub-efi-amd64-bin (= 2.04-1ubuntu28), grub-efi-amd64 |
> grub-pc
> 
> # dpkg -s grub-pc
> Replaces: grub, grub-common (<= 1.97~beta2-1), grub-coreboot,
> grub-efi-amd64, grub-efi-ia32, grub-ieee1275, grub-legacy, grub2 (<<
> 2.04-1ubuntu28)
> Depends: debconf (>= 0.5) | debconf-2.0, grub-common (=
> 2.04-1ubuntu28), grub2-common (= 2.04-1ubuntu28), grub-pc-bin (=
> 2.04-1ubuntu28), ucf, grub-gfxpayload-lists
> Conflicts: grub (<< 0.97-54), grub-coreboot, grub-efi-amd64,
> grub-efi-ia32, grub-ieee1275, grub-legacy, grub-xen
> 
> # dpkg -s grub-pc-bin
> Replaces: grub-common (<= 1.97~beta2-1), grub-pc (<< 1.99-1), grub2
> (<< 2.04-1ubuntu28)
> Depends: libc6 (>= 2.28), libdevmapper1.02.1 (>= 2:1.02.36),
> grub-common (= 2.04-1ubuntu28)
> 
> # dpkg -s grub2-common
> Replaces: grub, grub-cloud-amd64 (<< 0.0.4), grub-common (<< 1.99-1),
> grub-coreboot (<< 2.02+dfsg1-7), grub-doc (<< 0.97-29ubuntu60),
> grub-efi-amd64 (<< 2.02+dfsg1-7), grub-efi-arm (<< 2.02+dfsg1-7),
> grub-efi-arm64 (<< 2.02+dfsg1-7), grub-efi-ia32 (<< 2.02+dfsg1-7),
> grub-efi-ia64 (<< 2.02+dfsg1-7), grub-ieee1275 (<< 2.02+dfsg1-7),
> grub-legacy, grub-legacy-doc (<< 0.97-29ubuntu60), grub-pc (<<
> 2.02+dfsg1-7), grub-uboot (<< 2.02+dfsg1-7), grub-xen (<<
> 2.02+dfsg1-7), grub-yeeloong (<< 2.02+dfsg1-7)
> Depends: grub-common (= 2.04-1ubuntu28), dpkg (>= 1.15.4) |
> install-info, libc6 (>= 2.28), libdevmapper1.02.1 (>= 2:1.02.36),
> libefiboot1 (>= 37), libefivar1 (>= 37), liblzma5 (>=
> 5.1.1alpha+20120614)
> Breaks: grub (<< 0.97-54), grub-cloud-amd64 (<< 0.0.4), grub-coreboot
> (<< 2.02+dfsg1-7), grub-doc (<< 0.97-29ubuntu60), grub-efi-amd64 (<<
> 2.02+dfsg1-7), grub-efi-arm (<< 2.02+dfsg1-7), grub-efi-arm64 (<<
> 2.02+dfsg1-7), grub-efi-ia32 (<< 2.02+dfsg1-7), grub-efi-ia64 (<<
> 2.02+dfsg1-7), grub-ieee1275 (<< 2.02+dfsg1-7), grub-legacy-doc (<<
> 0.97-29ubuntu60), grub-pc (<< 2.02+dfsg1-7), grub-uboot (<<
> 2.02+dfsg1-7), grub-xen (<< 2.02+dfsg1-7), grub-yeeloong (<<
> 2.02+dfsg1-7), shim (<< 13)
> Conflicts: grub-legacy
> 
> 
> > > The Ubuntu grub2 source package's chopped up into many binary
> > > packages.
> > > 
> > > Neither "grub-pc" nor "" have anything really significant for
> > > booting
> >                          ^grub-efi-amd64
> > > an EFI system.
> 
> Thanks for the correction. I wonder what I did :)
> 
> 
> > This is the part which I didn't understand. Grub2 is the boot
> > loader,
> > so I guessed, because of that article, that handling of UEFI versus
> > the old BIOS-based standard was placed in those two packages (grub-
> > pc
> > and\ grub-efi-amd64). But, like you said, Grub is split into a LOT
> > more packages. There are no less than 46 packages with "grub" in
> > the
> > name.
> > 
> > What disturbes me, is that the "update-grub" script is in the
> > "grub-pc" package, but not in "grub-efi-amd64". Isn't this script
> > needed, for instance, when a new kernel is to be installed?
> 
> "update-grub" in "grub-pc" is the legacy "update-grub" script, which
> means that it is "update-grub" of grub1. Running grub1's "update-
> grub"
> would update "/boot/grub/menu.lst" in between "BEGIN AUTOMAGIC
> KERNELS
> LIST" and "END DEBIAN AUTOMAGIC KERNELS LIST" lines.

Does that mean that "update-grub" is obsolete? I recall vaguely that it
used to be executed whenever a new kernel gets installed. Is this no
longer the case with Grub2?

> > Obviously it isn't. But why is it split into the two packages?
> > Doesn't it matter, which package is installed? If not, why two
> > packages?
> > 
> > > localhost /tmp/GRUB $ dpkg -L grub-pc
> > > /.
> > > /usr
> > > /usr/bin
> > > /usr/lib
> > > /usr/lib/grub-legacy
> > > /usr/lib/grub-legacy/update-grub
> > > /usr/sbin
> > > /usr/sbin/upgrade-from-grub-legacy
> > > /usr/share
> > > /usr/share/bash-completion
> > > /usr/share/bash-completion/completions
> > > /usr/share/bug
> > > /usr/share/bug/grub-pc
> > > /usr/share/bug/grub-pc/presubj
> > > /usr/share/bug/grub-pc/script
> > > /usr/share/doc
> > > /usr/share/man
> > > /usr/share/man/man8
> > > /usr/share/man/man8/grub-bios-setup.8.gz
> > > /usr/bin/grub-ntldr-img
> > > /usr/sbin/grub-bios-setup
> > > /usr/share/bash-completion/completions/grub-bios-setup
> > > /usr/share/doc/grub-pc
> > > 
> > > localhost /tmp/GRUB $ apt download grub-efi-amd64
> > > 
> > > localhost /tmp/GRUB $ dpkg -x grub-efi-amd64_2.04-
> > > 1ubuntu28_amd64.deb
> > > .
> > > 
> > > localhost /tmp/GRUB $ lr
> > > .:
> > > grub-efi-amd64_2.04-1ubuntu28_amd64.deb  usr/
> > > 
> > > ./usr:
> > > share/
> > > 
> > > ./usr/share:
> > > bug/  doc/
> > > 
> > > ./usr/share/bug:
> > > grub-efi-amd64/
> > > 
> > > ./usr/share/bug/grub-efi-amd64:
> > > presubj  script*
> > > 
> > > ./usr/share/doc:
> > > grub-efi-amd64@
> > > 
> > > localhost /tmp/GRUB $ sudo apt install grub-efi-amd64 -s
> > 
> > What does that "-s" argument do? I couldn't find it in the man
> > page.
> 
> "-s" == "--simulate"
> 
> It shows what the apt/apt-get command would install.
> 
> It might not be in "man apt", but it must be in "man apt-get".
> 
> 
> > > Reading package lists... Done
> > > Building dependency tree
> > > Reading state information... Done
> > > The following packages will be REMOVED:
> > >   grub-gfxpayload-lists grub-pc
> > > The following NEW packages will be installed:
> > >   grub-efi-amd64
> > > 0 upgraded, 1 newly installed, 2 to remove and 0 not upgraded.
> > > Remv grub-gfxpayload-lists [0.7] [grub-pc:amd64 ]
> > > Remv grub-pc [2.04-1ubuntu28] [grub-efi-amd64-signed:amd64 ]
> > > Inst grub-efi-amd64 (2.04-1ubuntu28 Ubuntu:20.10/groovy [amd64])
> > > Conf grub-efi-amd64 (2.04-1ubuntu28 Ubuntu:20.10/groovy [amd64])
> > > th localhost /home/th
> > > 
> > > localhost /tmp/GRUB $
> > > 
> > > So if you install "grub-efi-amd64", nothing much'll change.
> > 
> > Thanks!
> 
> You're welcome!

Cheers,
Volker
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