grub-imageboot doesn't like nonstandard image locations

[Alexander List]

# apt-cache policy grub-imageboot grub-pc
grub-imageboot:
  Installed: 0.6
  Candidate: 0.6
  Version table:
 *** 0.6 0
        500 http://ch.archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
        100 /var/lib/dpkg/status
grub-pc:
  Installed: 2.02~beta2-6
  Candidate: 2.02~beta2-6
  Version table:
 *** 2.02~beta2-6 0
        500 http://ch.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status
grub-common:
  Installed: 2.02~beta2-6
  Candidate: 2.02~beta2-6
  Version table:
 *** 2.02~beta2-6 0
        500 http://ch.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

My /boot partition is rather small, so I tried an alternate location for .iso/.img files:

-----
# cat /etc/default/grub-imageboot
# Where to find the iso/floppy images

IMAGES="/var/lib/boot/images"

# You can override the boot options for iso/floppy images here
# see http://syslinux.zytor.com/wiki/index.php/MEMDISK for details

#IMAGEOPTS="rawimg"
#ISOOPTS="iso"
-----

update-grub2 finds everything:

-----
# update-grub2
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.13.0-7-generic
Found initrd image: /boot/initrd.img-3.13.0-7-generic
Found linux image: /boot/vmlinuz-3.13.0-5-generic
Found initrd image: /boot/initrd.img-3.13.0-5-generic
Found linux image: /boot/vmlinuz-3.2.54-030254-generic
Found initrd image: /boot/initrd.img-3.2.54-030254-generic
Found memtest86+ image: /memtest86+.elf
Found memdisk: /memdisk
Found iso image: /var/lib/boot/images/biosupdate.iso
Found iso image: /var/lib/boot/images/grml64-full_2013.09.iso
Found floppy image: /var/lib/boot/images/netboot.img
done
-----

When I reboot, I get:

-----
                         GNU GRUB version 2.02~beta2-6

 +----------------------------------------------------------------------------+
 | Ubuntu |
 | Advanced options for Ubuntu |
 | Memory test (memtest86+) |
 | Memory test (memtest86+, serial console 115200) |
 |*Bootable ISO Image: biosupdate |
 | Bootable ISO Image: grml64-full_2013.09 |
 | Bootable Floppy Image: netboot |
 | |
 | |
 | |
 | |
 | |
 +----------------------------------------------------------------------------+

      Use the ^ and v keys to select which entry is highlighted.
      Press enter to boot the selected OS, `e' to edit the commands
      before booting or `c' for a command-line.
-----

I select one of the image options, and get:

-----
error: file `/memdisk' not found.
-----

I reboot, and edit the commandline:

-----
setparams 'Bootable ISO Image: biosupdate' |
 | |
 | insmod part_msdos |
 | insmod lvm |
 | insmod ext2 |
 | set root='lvmid/V3HrbD-skk5-Fpvd-T6Yk-LXD6-4sKI-RyZdx3/jaqIpu-QacO-\|
 |dXRK-0A4f-A6vY-2JrG-NsJBVp' |
 | if [ x$feature_platform_search_hint = xy ]; then |
 | search --no-floppy --fs-uuid --set=root --hint='lvmid/V3HrbD-skk5\|
 |-Fpvd-T6Yk-LXD6-4sKI-RyZdx3/jaqIpu-QacO-dXRK-0A4f-A6vY-2JrG-NsJBVp' c12575\|
 |c9-ad18-4656-a169-384c2556499b |
 | else |v

                         GNU GRUB version 2.02~beta2-6

 +----------------------------------------------------------------------------+
 |dXRK-0A4f-A6vY-2JrG-NsJBVp' |^
 | if [ x$feature_platform_search_hint = xy ]; then |
 | search --no-floppy --fs-uuid --set=root --hint='lvmid/V3HrbD-skk5\|
 |-Fpvd-T6Yk-LXD6-4sKI-RyZdx3/jaqIpu-QacO-dXRK-0A4f-A6vY-2JrG-NsJBVp' c12575\|
 |c9-ad18-4656-a169-384c2556499b |
 | else |
 | search --no-floppy --fs-uuid --set=root c12575c9-ad18-4656-a169-3\|
 |84c2556499b |
 | fi |
 | linux16 /boot/memdisk iso |
 | initrd16 /var/lib/boot/images/biosupdate.iso |
 | |
 +----------------------------------------------------------------------------+

      Minimum Emacs-like screen editing is supported. TAB lists
      completions. Press Ctrl-x or F10 to boot, Ctrl-c or F2 for
      a command-line or ESC to discard edits and return to the GRUB menu.
-----

--> it works

When I set the image location back to the default of /boot/images, everything works as expected:

-----
root@zimba:/boot/images# update-grub2
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.13.0-7-generic
Found initrd image: /boot/initrd.img-3.13.0-7-generic
Found linux image: /boot/vmlinuz-3.13.0-5-generic
Found initrd image: /boot/initrd.img-3.13.0-5-generic
Found linux image: /boot/vmlinuz-3.2.54-030254-generic
Found initrd image: /boot/initrd.img-3.2.54-030254-generic
Found memtest86+ image: /memtest86+.elf
Found memdisk: /memdisk
Found iso image: /boot/images/biosupdate.iso
done
-----

The problem is that the grub root is set incorrectly if images are configured to reside outside /boot, and/or that memdisk isn't copied to IMAGEPATH/memdisk. MEMDISKPATH

-----
$ diff -ur grub.cfg-bootpart grub.cfg-varpart
--- grub.cfg-bootpart 2014-02-07 15:24:11.261689248 +0100
+++ grub.cfg-varpart 2014-02-07 15:25:32.661693188 +0100
@@ -284,16 +284,43 @@
 ### END /etc/grub.d/41_custom ###

 ### BEGIN /etc/grub.d/60_grub-imageboot ###
-menuentry "Bootable Floppy Image: dosdisk32M" {
+menuentry "Bootable ISO Image: biosupdate" {
  insmod part_msdos
+ insmod lvm
  insmod ext2
- set root='hd0,msdos1'
+ set root='lvmid/V3HrbD-skk5-Fpvd-T6Yk-LXD6-4sKI-RyZdx3/jaqIpu-QacO-dXRK-0A4f-A6vY-2JrG-NsJBVp'
  if [ x$feature_platform_search_hint = xy ]; then
- search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 a96dc997-c4ef-4beb-9fc7-89ce40bb2489
+ search --no-floppy --fs-uuid --set=root --hint='lvmid/V3HrbD-skk5-Fpvd-T6Yk-LXD6-4sKI-RyZdx3/jaqIpu-QacO-dXRK-0A4f-A6vY-2JrG-NsJBVp' c12575c9-ad18-4656-a169-384c2556499b
  else
- search --no-floppy --fs-uuid --set=root a96dc997-c4ef-4beb-9fc7-89ce40bb2489
+ search --no-floppy --fs-uuid --set=root c12575c9-ad18-4656-a169-384c2556499b
+ fi
+ linux16 /memdisk iso
+ initrd16 /var/lib/boot/images/biosupdate.iso
+}
-----

It is not entirely clear to me if the problem is in grub-imageboot or /usr/lib/grub/grub-mkconfig_lib, which is part of grub-common.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.