Ubuntu
casper package

[Hardy] 2.6.24 does not boot from USB

Bug #216565 reported by jesus
4
Affects Status Importance Assigned to Milestone
casper (Ubuntu)
Invalid
Undecided
Unassigned

Bug Description

package: kernel , casper

Build a Ubuntu Hardy in a USB Pendrive. (For example: make a copy of casper folder in a pendrive and set a grub bootloader, and install grub in MBR)
 1. Kernel loads
 2. Initrd loads
 3. Casper tries to find a path for .squashfs but never find it and stops into busybox

New Kernel 2.6.24 cannot find a usb boot device.

See dmesg picture

(This boot method has been successfully used in UbuntuiES ---gutsy kernel--- http://ubuntuies.com )

Revision history for this message
jesus (jesuslalvaro) wrote :
Revision history for this message
jesus (jesuslalvaro) wrote :

See also this casper.log trying to open /dev/scd0 instead of /dev/sdb

Revision history for this message
Peter Cordes (peter-cordes) wrote :

casper finds devices not by looking for /casper/filesystem.squashfs, but rather by checking .disk/casper-uuid.

in initramfs, scripts/casper:matches_uuid() looks like:
...
for try_uuid_file in "$mountpoint/.disk/casper-uuid"*
 ...

 extract an initramfs with zcat | cpio -i, if you want to look at /init or scripts/casper....

 If you didn't copy .disk from the CD, casper won't use filesystem.squashfs. There's a script called isotostick.sh linked to from https://help.ubuntu.com/community/Installation/FromUSBStick. It sets up syslinux and everything, though, so if you already have grub on your USB, use that. The .disk thing should be all you need.

Also note that you can copy a .iso to a USB stick and boot vmlinuz+initrd.gz with
boot=casper iso-scan/filename=/intrepid/intrepid-desktop-amd64.iso

 That makes it easier to have multiple bootable CDs on a USB stick at the same time.

 but watch out for linux not detecting your USB drive before it creates the list of devices to scan for the .iso. I put break=mount in my syslinux.cfg, to pause while stuff is detected. https://bugs.launchpad.net/ubuntu/+source/casper/+bug/158976

Changed in casper:
status: New → Invalid
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