Re: Possibly erroneous "device not present" message during boot

[Richard Owlett <rowlett@cloud85.net>]

On 04/12/2017 02:23 PM, Brian wrote:
> On Wed 12 Apr 2017 at 13:33:02 -0500, Richard Owlett wrote:
>
> > On theory "too much better than too little" I see:
> > <begin quote>
> > ### BEGIN /etc/grub.d/20_linux_xen ###
> >
> > ### END /etc/grub.d/20_linux_xen ###
> >
> > ### BEGIN /etc/grub.d/30_os-prober ###
> > menuentry 'Debian GNU/Linux (8.6) (on /dev/mmcblk0p1)' --class gnu-linux
> > --class gnu --class os $menuentry_id_option
> > 'osprober-gnulinux-simple-380e2a6d-f851-4fd1-9db2-869a0982b511' {
> > 	insmod part_msdos
> > 	insmod ext2
> > 	if [ x$feature_platform_search_hint = xy ]; then
> > 	  search --no-floppy --fs-uuid --set=root
> > 380e2a6d-f851-4fd1-9db2-869a0982b511
> > 	else
> > 	  search --no-floppy --fs-uuid --set=root
> > 380e2a6d-f851-4fd1-9db2-869a0982b511
> > 	fi
> > 	linux /boot/vmlinuz-3.16.0-4-686-pae root=/dev/mmcblk0p1
> > 	initrd /boot/initrd.img-3.16.0-4-686-pae
> > }
> > <end quote>
>
> GRUB is content to boot whatever is on the SD (as you observe) so must
> be happy enough with the stanza above; there is no problem with booting
> there. Actually, GRUB only uses
>
>  linux /boot/vmlinuz-3.16.0-4-686-pae root=/dev/mmcblk0p1
>
> and
>
>  initrd /boot/initrd.img-3.16.0-4-686-pae
>
> to get everything up and running. Without those two lines you would not
> be booting.
>
> So try this:
> When the GRUB menu displays press the "e" key and remove the
>
>   search --no-floppy --fs-uuid --set=root 380e2a6d-f851-4fd1-9db2-869a0982b511
>
> Then press the "F10" key. Can you still boot? Do you get the onscreen
> message you are concerned about?

Something *ODD* is going on in that area.
As that string appears in both the "then" and "else" clauses I:
  1. tried removing them individually leaving a blank line.
     For both cases grub crashed with a syntax error.
  2. removed entire if-then-else-fi construct.
     That booted without the "device not found" message.
  3. changed the last digit of the UUID.
     That demonstrated that the "then" clause was the one executed.
  4. used gparted to change the UUID of the SD card.
     That crashed in ways seemingly unrelated to anything.
     I'm going to update my preferred preseed.cfg and reinstall to
     both /dev/sda1 and the SD card in a reproducible way.

What log files should I save after each test boot.