By Dominic Duval, Red Hat Certfied Engineer
There are situations, namely in emergency mode, where the USB drivers won’t be available. So you won’t even be able to enter a command. This is due to the fact that in emergency mode all drivers need to be provided in the initrd file under /boot, and USB is not there by default. The trick is to add those drivers, so that they will be available earlier. The ‘mkinitrd’ command can do precisely that with the ‘–with’ argument (this only works under RHEL4):
Add a new entry in your grub.conf file (always do backups!) that points to this new initrd image, and you’re done! Your USB keyboard now works in emergency mode.