Got this error while upgrading from Ubuntu 10.10 to 11.04>The disc drive for / is not ready yet or not present. Continue to wait, press S to skip or M for manual recovery.

Searched for solution and found this Ubuntu bug https://bugs.launchpad.net/ubuntu/+source/udev/+bug/753853

Solution given was do run command

sudo apt-get install -f Reason given was

Broken branding-ubuntu package was causing apt to stop prematurely leaving the system in an inconsistent state.