Comment 5 for bug 206217

And here's a screenshot of what rebooting from a r/o fs looks like with my hackish patch applied (image attached in case there are any typing errors on my part. I disabled some debug "echo here"s in the patch).

...
* Disabling laptop mode...
/etc/rc6.d/K99laptop-mode: 85: cannot create: Directory nonexistent.
rm: missing operand
Try `rm --help' for more information.
* Terminating all remaining processes... [OK]
...

(and reboot finishes properly without hanging).

I should also note that it might be the filesystem containing /var that is the problem - I have only / and /home on this machine, so I haven't debugged that further.