Comment 5 for bug 573975

Thanks a lot Alkis for your suggestions. The compiz proved to be the key
trick. Let me explain what finally needed to be done to get my two clients
running, for posterity. Client A is a desktop with a A7V8X-MX motherboard,
AMD Athlon XP, circa 2003. Client B is a Dell Inspiron 8100 laptop with the
hard drive removed. Both are booting with the onboard PXE capability.
If you have older clients running older versions of LTSP/Ubuntu, listen up.

First edit /etc/default/tftpd-hpa and change the TFTP_OPTIONS:
TFTP_OPTIONS="--secure"
then restart service: sudo service tftpd-hpa restart
(This seems like a bug that Ubuntu should fix!)

Try running after this if you're feeling lucky! I wasn't, for either client.
Run Alkis' suggested command to disable compiz:
sudo gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory --type string --set /desktop/gnome/session/required_components/windowmanager metacity

Try running again. My client B worked, but not A. You may notice that your
image is 500 MB whereas in earlier versions of LTSP/Ubuntu it was 200 MB!
Edit file /etc/ltsp/ltsp-update-image.conf and change the NO_COMP definition to be
NO_COMP="-no-exports", which will restore squashfs compression. Run
sudo ltsp-update-sshkeys
sudo ltsp-update-image --arch i386
(Omit the --arch i386 if you're not building a 32-bit client.)
This got both my clients running, and B boots 3 seconds faster.

For general debugging I recommend also doing:
sudo cp /opt/ltsp/i386/etc/lts.conf /var/lib/tftpboot/ltsp/i386/lts.conf
and then adding the lines Alkis recommends above into the /var/lib version.
It's a lot easier to get error messages from the console than from flashing
X displays!

The only thing left not working for me is sound on client A. In .xsession-errors
it complains about "/usr/bin/asoundconf: not found" which is true.
Package asoundconf-gtk doesn't provide this either. I'm not a heavy user
of sound on this client, though.