I've read about a trick to fix the USB keyboard problem although I have never tried it myself. I wanted to, but couldn't find the right sort of device.
Anyway the trick was the find a USB device that takes a while to process so as to keep the USB initialization BIOS busy long enough to press the keyboard keys. Or a buggy device that locks it up until removed. Then you can press the BIOS entry key and remove the device to continue.