After rebuilding the system's initrd with "dracut -f" the system hangs on boot

Issue

• After rebooting the system with a new initrd created with dracut -v -f, the system hangs with the following displayed:

dracut: FATAL: No or empty root= argument
dracut: Refusing to continue

Kernel panic - not syncing: Attempting to kill init!
Pid; 1, comm: init Not tainted 2.6.32.279.14.1.el6.x86_64 #1

• The /etc/grub.conf has the 'root=' flag missing. The error above is following the addition of the missing 'root=/dev/mapper/vg00-lvolvol' to kernel line in /boot/grub/grub.conf file.