Comment 3 for bug 519882

This is a side effect of bug 519855
The workaround is to open a terminal and run the following command:
$ cd /lib/udev
$ sudo ln -s firmware firmware.sh
$ sudo dpkg --configure -a

Or wait a few hours until the update is available on your mirror.
Don't forget to remove the symlink before upgrading to the newest release of the faulty package.

Rebooting with after this error may or may not work depending on your hardware.