squashfs errors; work around by combining CD with USB boot?

[Silas S. Brown]

When attempting to install Lubuntu 11.04 on an old laptop (in response to one of those "my old laptop doesn't run Windows anymore" help requests from a friend), I was getting squashfs errors from the install CD that were causing random failures and general chaos, although the CD boot menu's integrity check did pass. I tried using the boot options mentioned at https://help.ubuntu.com/community/SquashfsErrors but this did not help. (The exact symptoms varied with each boot attempt. Sometimes it would fail to load the X11 environment and drop me to a prompt; other times it would load X11 and LXDE successfully but partman or one of the other installation modules would crash.)

However, an old Knoppix 5 CD (which also uses squashfs) loaded without trouble on the same hardware, as did an old Debian 3 install CD, so I did a minimal install of Debian 3, booted into it, set its /etc/apt/sources.list to a Debian archive site, dist-upgrade to Debian 4, reboot, change the kernel from 2.4 to 2.6, reboot, dist-upgrade to Debian 5, reboot, dist-upgrade to Debian 6, reboot, and proceed with installation of lxde etc. (What a headache.) It seems that older versions of Linux are more likely to be OK with old CD drives, so we have to do lengthy workarounds like this.

I did have an Lubuntu "Live USB" stick that I had made by mounting the iso with -o loop and copying its files to a USB stick, renaming isolinux files to syslinux, and running syslinux. That "Live USB" version of Lubuntu boots absolutely fine on modern laptops (sometimes requires Esc to be pressed to access a boot device menu), but the old laptop was of course too old to boot from USB.

It ought to be possible to boot from an Lubuntu CD but tell it to read its filesystem from USB instead of CD. That should work around squashfs errors. It might be possible to make such a version by adapting the instructions at http://www.pendrivelinux.com/make-a-usb-boot-cd-for-kubuntu-9-10/ but I did not try this because I'd run out of blank CDs.

It would be nice if Lubuntu could officially support:
(1) creating a USB version as well as the CD version (just put up some instructions to do as I did above re syslinux),
(2) giving the CD version an option to find its files on USB or other media, to work around any problems with reading the CD on old hardware that can't boot from USB but can still read it.

Incidentally another workaround I tried was to do a network install by downloading "linux" and "initrd.gz" from http://archive.ubuntu.com/ubuntu/dists/natty/main/installer-i386/current/images/netboot/ubuntu-installer/i386/ and putting them into /boot with a customized /boot/grub/menu.lst in a temporary Knoppix install ("sudo knoppix-installer" from the live CD gives a Debian-like system). I successfully booted into the network installer but Lubuntu was not an option so I chose Xubuntu. It installed OK but it did not boot; machine just hangs on a black screen. I didn't pursue that option any further but switched to the Debian install I described above. Hopefully when Lubuntu becomes an official Ubuntu flavour it will be available in the network install menu, but we'll have to wait and see if the black-screen crash is still around. But as we might sometimes need to install Lubuntu when a fast network connection is not available, it would be nice to have the above-mentioned CD+USB option as well.

[Silas S. Brown (ssb22)]

It's possible that a "Plop Boot Manager" CD would have helped me load Lubuntu from the USB drive. http://www.plop.at/en/bootmanager.html

(I did not try this, since I've already returned my friend's laptop with Debian 6 on it.)

[Chris Guiver (guiverc)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to look at all reported bugs in a timely manner. There have been many changes in Ubuntu since that time you reported the bug and your problem may have been fixed with some of the updates. It would help us a lot if you could test it on a currently supported Ubuntu version. When you test it and it is still an issue, kindly upload the updated logs by running only once:
apport-collect <bug #>

and any other logs that are relevant for this particular issue.

Note: SQUASHFS errors are representative of bad media issues, either the download failed, or the write to cd/thumb-drive failed - refer to https://manual.lubuntu.me/1/1.3/installation.html and the "Check disk for defects" option which will detect and warn you of these.