I'm going to write "not going to happen". Here's why. I've yet to see a BIOS offer to boot the parallel port ZIP drive. However, some IBMs did offer a Zip drive in the laptop and ... it was bootable.
If you are trying to solve some CD/hard-disk boot problem, let me note I will not respond in this thread since that was not in your initial post.
iomega zip Parallel Port
How can i make my iomega become my start up device. How do i add it to my startup in the configuration.