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

On Thu 13 Apr 2017 at 10:17:23 -0500, Richard Owlett wrote:

> On 04/12/2017 02:23 PM, Brian wrote:
> >
> >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.

I'm not sure this would be a good idea without reconstructing the if...fi

>   2. removed entire if-then-else-fi construct.
>      That booted without the "device not found" message.

This is a much better technique than the one I suggested, which is a
little unclear as to what to remove. A GRUB stanza does not need a
search line or what is between if and fi. It can be useful, but the
linux and initrd lines are sufficient much of the time.

>   3. changed the last digit of the UUID.
>      That demonstrated that the "then" clause was the one executed.

This confirms your second point.

>   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.

I'm afraid I'm not going to try this. Off the top my head I'd expect the
device still to boot with a suitable GRUB stanza

"Erroneous" isn't a bad description of the message. As you describe it
the boot proceeds whether or not the "ENTER" key is pressed. It would be
interesting to know why the UUID is not recognised. Perhaps a small bug
in GRUB? It is a minor inconvenience. A LABEL is the way to go but I
think 'update-grub' will only generate a search line with a UUID in it.

> What log files should I save after each test boot.

The issue arises with GRUB. The will be no records in the logs as the
system has not booted.