HP makes printers, but not digital camera and optical drives. They have always rebadged OEM units made by Ricoh, LG, Lite-On, BenQ, NEC, Samsung, and so on, mostly Taiwanese, and some Japanese and South Korean. Even after outsourcing to Taiwan, Sony and Philips play some important roles in designing and making DVD writers. I doubt there's a single component or firmware designed by HP in DVD writers.
Since DVD writers are getting less and less profitable and HD-DVD is getting closer to retail, it's only logical to expect NEC to give up DVD sooner or later
and concentrate on HD-DVD.