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




On Fri 14 Apr 2017 at 12:05:38 -0500, Richard Owlett wrote:

> On 04/13/2017 05:55 PM, Brian wrote:
> >On Thu 13 Apr 2017 at 20:05:22 +0200, Pascal Hambourg wrote:
> >
> >>David is right : you don't really boot from the SD card.
> >
> >The OP never claimed he was booting from the SD card. He particularly
> >said he did not install GRUB to the card.
> >
> >>GRUB is on the HDD. The kernel is on the HDD. Only the root filesystem is on
> >>the SD card.
> >
> >Yes. That's what the linux line says too.
> 
> I'll try to clarify some details.

Your previous descriptions were good; clarification cannot do any harm.

> My installation protocol.
>  1. I always use "Expert" as that way the installer will
>     do fewer things I'm not aware of.

Very wise. If you are familiar with each stage of the installation you
can more more easily spot anomalies. "Expert"=="more control".

>  2. I only install Grub the *first* time I do a Debian install.
>     By poor design Grub puts the current install first on menu.
>     When experimenting with configuration as I do, the least
>     likely install to be functional is the latest.
>     This requires me to run update-grub on the "good" install.

That's ok. I tend to be more promiscuous; usually on a whim, like
wanting to put a particular entry at the top of GRUB's menu list.

When you do 'update-grub' do you still get no "set root=" line for the
SD card in the grub.cfg?

>  3. Similarly a swap partition is specified only on the first
>     install as the installer insists on destroying the UUID of
>     the existing swap partition. It is simpler to edit only the
>     fstab of latest install than to edit those for all other
>     installs each time.

That's ok too. I often don't bother with a swap partition. Some of my
machines have less than 4 GB of disk space. I see space for packages as
more important than swap space. 

>  4. All installs in this thread have been done using DVD 1 of
>     13 of Debian 8.6.0 - thus all intrinsically use the same
>     kernel.

Yes.

> I've done some additional observations and test installs.
> 1. The BIOS of the Lenovo T510 can be directed to boot from
>    the CD/DVD drive, hard disk, or any attached USB flash
>    drive. It *cannot* be directed to boot from the SD card.

I'm at a disadvantage here. I do not have an SD card. I do not have a
USB hub. However, I thought USB sticks and SD cards were the same (or
at least similar) when it came to booting.

> 2. I did an install to a USB flash drive including installing
>    Grub2 to the MBR of that flash drive. When selecting the
>    SD card from the grub menu I see nothing different.

Does that not substantiate what I said just now? 

> 3. I did a new install to the SD card specifying a different set
>    of packages and installing grub to the MBR of the SD card.
>    Once again no behavioral difference.

I cannot believe your install to the card would be capable of criticism.

> Does any of this justify a bug report. Especially as I do not
> have the bandwidth to do a netinstall of a pre-release version?

I mentioned "bug" in another mail. I wish I hadn't. It is not that bugs
in GRUB or the Debian grub package do not arise, but I'd want to know
more about SD cards before committing myself.

-- 
Brian.