Ubuntu 13.10 was released a few days ago and I upgraded one of my machines. Everything went fine until I had to reboot. Choosing entries in the grub menu worked flawlessly but as soon as I had to enter my passphrase to unlock my encrypted partitions my keyboard (USB) no longer was working – it was dead. As I don’t have the option to use a PS/2-Keyboard (not owning such a keyboard, machine has no PS/2 port) I was locked out of my system.
The bug report on Launchpad [1] brought me the solution. After booting an older kernel (3.8 iirc) I just added the line “ohci_pci” to /etc/initramfs-tools/modules and executed sudo update-initramfs -u.
This fixed it for me. If you have no older kernel installed you might be able to boot your system with a live cd and mount your encrypted partitions. With chroot it should be possible to update the initramfs on your machine.
[1] https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/1238194