Comment 11 for bug 86666

indeed, this is a sign of a kernel hard crash -- your kernel died and, just before giving up the ghost, tried to give you an indication is was going down.

And... this, again, makes it much more difficult, since we do not know what happened. It would probably have been written to the console, but we do not seem to have access to it. Perhaps an option would be to send the console output to a serial -- and then we would know where it died.

Habbit -- can you add in here the lspci -vv, lspci -nvv, dmesg of a good startup and the boot log (whatever was saved) of a bad one? We can try to find out what is similar in your environment with Timo's one.