I learned that Super might mean 2.88MB FDDs. I don't know if it holds true, but that is not my concern.

@cordata51: The DD utility writes the image as raw as any other utility and it doesn't change the outcome "Operating system missing". The other thing of course is that I'm not trying to boot 32-bit OS, but a 64-bit one but I hope this doesn't change anything.

What solution I came to right now is that I let the HP Utility to make my USB bootable and not modify the boot sector. I only modify the files on it. The problem with this approach is that when I launch some 3rd party hdloader, it doesn't find a floppy to boot from ('cuz I don't have it) and neither the msetup.exe (which I have, but its at USB:\msetup.exe not C:\ as expected).