This weekend, one of our servers running Lucid has installed some upgrades:

libgcrypt11 1.4.4-5ubuntu2.1
linux-firmware 1.34.14
linux-image-2.6.32-41-generic 2.6.32-41.91
linux-libc-dev 2.6.32-41.91

Afterwards, it rebooted since this was a kernel upgrade. Now, it hangs at booting, after /scripts/init-bottom. init-bottom itself should not be the problem, the last line I can see is "done". So the problem has to be shortly after that.

http://manpages.ubuntu.com/manpages/hardy/man8/initramfs-tools.8.html tells me, that the next step is

procfs and sysfs are moved to the real rootfs and
execution is turned over to the init binary which
should now be found in the mounted rootfs.

But I don't know how and where. The problem exists with older kernels too, and this one here doesn't fix the problem: http://www.tummy.com/journals/entries/jafo_20111003_160440

Anyone an idea?