On Thu 15 Jul 2021 at 22:15:59 (+0200), Stella Ashburne wrote:
> > Sent: Thursday, July 15, 2021 at 7:08 PM
> > From: "David Wright" <deb...@lionunicorn.co.uk>
> >
> > Best I can do. (And I see that your kernel's naming of sda/sdb
> > is more stable than on at least a couple of my machines.)
> >
> What did you mean by "more stable"?

(Greg covered this.)

> > It might be worth posting a request for the stanza I asked for,
> > but as a new topic with a specific Subject line.
> 
> What "stanza" were you referring to? Was it Reco who posted it? And you wrote 
> that it was posted some time in June?

The /full/ stanza is next, but Grub probably makes this look more
complicated by adding more flexibility than any one user could
ever need. (It's GRand Unified …, after all.)

menuentry 'Debian GNU/Linux' --class debian --class gnu-linux --class gnu 
--class os $menuentry_id_option 
'gnulinux-simple-80318fa0-5915-4cc3-bc7c-99af2cfbfda9' {
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod ext2
        set root='hd0,gpt2'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 
--hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2  
700b607c-ffa6-4435-a4b6-10894928c764
        else
          search --no-floppy --fs-uuid --set=root 
700b607c-ffa6-4435-a4b6-10894928c764
        fi
        echo    'Loading Linux 5.10.0-7-amd64 ...'
        linux   /vmlinuz-5.10.0-7-amd64 
root=UUID=80318fa0-5915-4cc3-bc7c-99af2cfbfda9 ro  quiet
        echo    'Loading initial ramdisk ...'
        initrd  /initrd.img-5.10.0-7-amd64
}

That boots the encrypted root installation that I made the other day,
but I can boot the system manually just by typing C at the grub menu,
and then:

Grub> set root='hd0,gpt2'
Grub> linux /vmlinuz-5.10.0-7-amd64 ro quiet 
root=UUID=80318fa0-5915-4cc3-bc7c-99af2cfbfda9
Grub> initrd /initrd.img-5.10.0-7-amd64

or the second line can be shortened to:

Grub> linux /vmlinuz-5.10.0-7-amd64 ro quiet root=LABEL=viva05

or even:

Grub> linux /vmlinuz-5.10.0-7-amd64 ro quiet root=/dev/dm-0

because, once the disk's 5th partition has been unlocked,¹ any of
these properties describes the filesystem inside².

> > I can't see
> > why you shouldn't be able to boot your system with manual Grub
> > commands.
> 
> I thought so too. GRUB developers would and should have built a "Rescue Mode" 
> by just entering the commands.

They have, and you're using it. No, what I meant was that you should
be able to boot it, just giving the correct raw commands. The problem
is knowing what those correct commands are.

¹ Skip this; it's just for the record. Before I made this encrypted
  installation, I posted that you might need to load Grub modules
  like crypto, cryptodisk and luks. However, I now think that these
  modules may exist for unlocking /boot (which would have to be done
  by Grub) rather than / (which can be left for initrd to do).

² root=UUID=80318fa0-5915-4cc3-bc7c-99af2cfbfda9 was copied from grub.cfg,
  root=LABEL=viva05 was a LABEL set in the screen dialogue already posted,
  root=/dev/dm-0 was the device mapper I observed when I first booted the
  system (using Grub's menu).

Cheers,
David.

Reply via email to