Hmm, looks like they don’t have an option in the BIOS to reflash from USB, either. That’s sorta annoying, now that I look at it.

There’s probably some way to run their .exe under Wine to extract the .rom file, then use something like http://www.coreboot.org/Flashrom to do the flashing. I haven’t tried any such method, so I can’t say whether it’ll work. I suppose another option is to try to get a Windows bootable CD like http://www.nu2.nu/pebuilder/ built, then use run the HP flasher under that.