casper boot doesn't work with some boot options

It should not be necessary to specify root=UUID=46F1-C9E3 when booting with boot=casper. It will look through the disks and find the live CD by checking .disk/uuid.

Can you please attach casper.log (see https://wiki.ubuntu.com/DebuggingCasper)?

Eliminating root=UUID=nnnn works the same;

if I had one of the option (e.g. xforcevesa for this test) the system doesn't boot and stop in initramfs saying "unable to find a medium containing a live file system"

The live file system is correctely found if those problematic booting options are not sent to kernel
The system beeing unbooted, I tried to follow indications to save casper.log but :

1) I do no have a second usb port to use for saving data;

2) mounted first hd and saved casper.log, which only says it can't find media.

Thanks. Please attach dmesg output as well (dmesg > dmesg.txt) and add "debug" to the boot options so that we can get more info in casper.log.

You are not using an editor to edit grub.cfg or menu.lst which wraps lines so they are cut in two?

I added debug to boot options and I see the system booting even if I have xforcevesa option;
It seems to work from a cold start, but not in rebooting.
In the pc needing vesa driver, the option has no effect - the video doesn't work correctly (in standard bootings when kernel is charged with xforcevesa the video works OK)
I'm editing menu.lst (and never edited grub.conf) from nano or gedit, or, more frequently, from grub itself at start;

and here dmesg.txt

The dmesg confirms that the whole kernel line is intact, so it is not an issue of line wrapping in the text editor:

[ 0.000000] Kernel command line: floppy.allowed_drive_mask=0 boot=casper noprompt cdrom-detect/try-usb=true lang=it locale=it_IT xforcevesa debug

I am not sure xforcevesa is supported any longer.

I guess the above logs are from a successful boot? Are you able to provide these logs for a failed boot?

I do no know how to save a boot log of a failed booting

You did it comment 2, right? casper.log (when booting with "debug") and a dmesg.txt will do.

If this is the same problem I had, I have a fix.

My old pc cannot boot from USB. I put kernel and initrd on a spare hard disk partition, and the root filesystem.squashfs on the usb stick /dev/sdb1. This works with boot option: live-media=/dev/sdb1. This boot option is documented in: http://manpages.ubuntu.com/manpages/karmic/man7/casper7.html , but ubuntu 11.10 does not support it. I could easily fix this, and/or do not understand why the missing code disappeared. See attached patch.

oops, I made the patch the wrong way, the 'minus' lines should be added of course.

To see the usefulness of the live-media boot option, please refer to (my edit in) https://help.ubuntu.com/community/Installation/FromLinux

This bug was fixed in the package casper - 1.326

---------------
casper (1.326) quantal; urgency=low

  * 22desktop_settings:
    - Rename 22screensaver to 22desktop_settings
    - Move 22gnome_panel_data's content to 22desktop_settings
    - Flush overrides in 22desktop_settings to avoid getting duplicate keys
      when using persistence.
    - Check for gsettings-desktop-schemas instead of gnome-panel-data
  * 35fix_language_selector:
    - Use sed against the original file (from rofs) instead of the target file.
      This avoids another case where the change is re-applied at every boot
      when using persistence.
  * 25adduser:
    - Remove RUNNING_UNDER_GDM from /etc/environment which was a big hack
      for back when we still used xscreensaver and was getting appended with
      every single boot.
    - Use /etc/sudoers.d instead of appending to /etc/sudoers, avoid getting
      duplicate lines with every reboot.
  * 23networking:
    - Change default /etc/network/interfaces to match that in /rofs, makes it
      easier to diff /etc when debugging casper.
  * casper-init, casper, 19-keyboard, casper-functions:
    - Remove any remaining reference to usplash as it's been deprecated for a
      long long time and just makes things harder to read.
  * casper-update-initramfs:
    - Exit when called from a non-writable media (cdrom) or when called from
      ubiquity. This fixes a > 1 minute wait when clicking "Try Ubuntu".
  * 19keyboard:
    - Add code to detect that the keyboard layout changed from the previous
      value and flush the gsettings key so that the indicator is properly
      reset. (LP: #946406)
  * 43disable_updateinitramfs:
    - Don't try to chmod a dangling symlink.
    - Only write /usr/sbin/update-initramfs if it doesn't already exist.
  * postinst:
    - Remove code generating symlink for /usr/sbin/update-initramfs to
      /usr/share/casper/casper-update-iniramfs as the diversion and symlinking
      is done in the initramfs and that code was only useful when the shim was
      first introduced. (LP: #984276)
  * scripts/casper:
    - Allow specifying live-media on the command line, helps when booting
      computers that are unable to boot a CD/USB disk. (LP: #423616)
    - Fix NFSOPTS handling by adding the needed comma and sticking it to the
      existing "ro" option of nfsmount (LP: #476208)
  * 22serialtty:
    - Move 22serialtty to 26serialtty to avoid overriding the newly generated
      upstart jobs. Note that this will spawn getty instead of login, but
      it's probably for the best as we need a specific baudrate. (LP: #747888)
 -- Stephane Graber <email address hidden> Tue, 02 Oct 2012 18:11:44 -0400