I think there was a version of the minimal-install-CD where an USB keyboard was usable when adding kernel parameters on boot. An example would be something like "gentoo nodhcp nofirewire" or "memtest". I guess this has something to do with grub. In that case this may be a duplicate of 6372. In that case 6372 sould be reopened. The keyboard can be used prior booting gentoo, for example for entering the BIOS setup using one of the "function keys" (e.g. F2)! Reproducible: Always Steps to Reproduce: Expected Results: Entering grub command line parameters should be possible prior loading the kernel on the minimal-install-CD. I didn't test the live-CD or live-DVD but I guess it's the same.
looks like it works ...