Ubuntu installation from USB-Stick: no medium found

[iRon]

Binary package hint: casper

I have tried to install edgy knot2 (desktop-amd64 version) from my USB-Stick, but the casper init script cannot find my USB-Stick.

I should notice that my computer has one Serial-ATA hard disk (/dev/sda) and one DVD-Drive (/dev/hda). The USB-Stick is normaly /dev/sdb.

Steps to reproduce:
- Prepare a bootable USB-Stick with syslinux
mount the edgy-desktop-amd64.iso and copy the folders casper, dists, install, pool and preseed to your USB-Stick. Also copy all files from the folder isolinux and the files initrd.gz and vmlinuz from the folder casper to your USB-Stick root
rename the isolinux.cfg to syslinux.cfg
edit the syslinux.cfg and remove the /casper/ before the inird.gz and vmlinuz and for better debugging remove the quiet and splash parameters
now boot from the USB-Stick and it will bring some error messages and then give you a prompt (for detailed error messages see the attached casper.log)

After some debugging I found out that the function find_livefs() in the /scripts/casper file of the initrd.gz package cannot find my USB-Stick. So if I modify the file so that the function only mount the /dev/sdb device then it will boot completely in the desktop environment.

By analyzing this function I found several critical sections, but I cannot repair this problem, because of my bad bash scripting knowledge (even worser than my English :D ). Here is what I have found out so far:

The get_fstype() function return the error message:
/init: /init: 1: cannot open /dev/hda: No medium found
This happens at the “eval $(fstype < /dev/hda)” line, because this device is my DVD-Drive and he can find no medium because there is no CD in it.

The next error message is:
mount: Cannot read /etc/fstab: No such file or directory
This happens because the get_fstype returns nothing and so the fstype variable will be empty and the command “mount -t ${fstype} -o ro "$devname" $mountpoint || continue” will fail.

So even if he ignores the empty /dev/hda the script fails at the is_usb_device() function. The following if statement will never be true:
if /lib/udev/path_id "${sysfs_path}" | grep -q "ID_PATH=(usb|pci-[^-]*-usb)"; then
Because I have no idea of regular expressions, i don't know why it does not work but when I execute the command “/lib/udev/path_id "/block/sdb"” in a shell it will give the following output:
sed: -e Ausdruck #1, Zeichen 102: Invalid range end
sed: -e Ausdruck #1, Zeichen 102: Invalid range end
ID_PATH=usb-0x0457-0x0151:0:0:0

If someone can fix this but cannot reproduce the error, he can send me the fixed casper script and I will test it.

[iRon (louuu-deactivatedaccount)]

Here is the casper.log file

[Tormod Volden (tormodvolden)]

Please try the patch in bug #57620 and report any success there.

[iRon (louuu-deactivatedaccount)]

I noticed that the output of the “/lib/udev/path_id” differs if I will take the one of the initrd.gz archive (before I have taken the one of my dapper installation). The correct output is:
ID_PATH=pci-0000:00:02.1-usb-0:5:1.0-scsi-0:0:0:0

[iRon (louuu-deactivatedaccount)]

I have tried the patch and it works just fine, so now the live system will completely boot. The bug #58730 is solved for me.