Bug#696877: installation-reports: Wheezy DI-b4-amd64-netboot-mini.iso from an usb stick fails trying to install grub

[Paul Bryan Roberts <pbronline-debian@yahoo.co.uk>]

On 23/01/13 21:42, Steven Chamberlain wrote:
> Hi,
>
> It looks like some code is already there to avoid cdrom or USB install
> media being used as the grub-install target.
>
> In the grub-installer script:
> >   552 # [...] if /cdrom seems
> >   553 # to be a USB stick then (hd0) may not be safe.  If we hit either of those
> >   554 # checks, then try the disk containing /boot instead.
> >   555 # The same goes for /hd-media, so avoid installing there as well.
> >   556 cdsrc=$(mount | grep "on /cdrom " | cut -d' ' -f1)
> >   557 cdfs=$(mount | grep "on /cdrom " | cut -d' ' -f5)
> >   558 hdsrc=$(mount | grep "on /hd-media " | cut -d' ' -f1)
> For hybrid media on USB it seems that /cdrom will be iso9660, so the
> next thing preventing an install to (hd0) is if cdrom-detect/hybrid is
> set to true.
>
> This seems a bit of a long shot, but in cdrom-detect it looks like this
> might go wrong if `list-devices cd; list-devices maybe-usb-floppy` finds
> the install media before `list-devices usb-partition` does.
>
> If someone who has hardware that can reproduce this, could please do the
> following, it could really help explain this:
>
> 1. boot a USB install up to the 'Configure the network' step,
> 2. drop to the Alt-F2 shell,
> 3. run these commands and note the output from them:
> # mount | grep cdrom
> # list-devices cd
> # list-devices maybe-usb-floppy
> # list-devices usb-partition
> # list-devices disk
>
> Thanks!
> Regards,
Hi,

Here's the output on a (laptop) machine of mine ...

# mount | grep cdrom
# list-devices cd
# list-devices maybe-usb-floppy
# list-devices usb-partition
/dev/sda4
# list-devices disk
/dev/sda

At this stage, all the installer can see is the USB stick.

I let the installer run on to the partition disks section and the output 
is then ...

# mount | grep cdrom
# list-devices cd
/dev/sr0
# list-devices maybe-usb-floppy
# list-devices usb-partition
/dev/sda4
# list-devices disk
/dev/sda
/dev/sdb

So in grub terms the hard-drive is disk 1.


After the original installation, /boot/grub/device.map read:

(hd0)   /dev/disk/by-id  /usb-BUFFALO_ClipDrive_A3200510210000751-0:0
(hd1)   /dev/disk/by-id/ata-Hitachi_HTS545025B9A300_100411PBN2061SFS47GT

and /boot/grub/grub.cfg had several set root='(hd1,msdos?)' statements.
This stuck me as not quite right so I deleted device map and ran 
update-grub.


To avoid confusion, I don't think I'm using a 'hybid media on USB'.
I threw together a USB image with both 32- and 64-bit mini.iso and
a syslinux menu to choose between them.  I didn't go anything specific
to create a USB/CD hybird.

I hope this helps.  I'm willing supply more information if asked.

Regards,

--
Paul Bryan Roberts
pbronline-debian@yahoo.co.uk