As far as I've tested, none of the HP machines boot from USB properly. There are exceptions like external FDDs and ODDs, but that is not very interesting. I need to boot from USB stick plugged into a random port.

1) The servers do have some kind of possibility to boot from USB, but they don't recognize all drives and show them as ¤"#!¤&%#)¤/& or some other wierd characters. Maybe recent BIOS updates will fix them...

2) HP desktops won't allow you to boot from any kind of USB sticks, but show you "operating system missing" in any position. Even if legacy USB is enabled etc.

3) HP notebooks are horror. There you can set the order in BIOS in which the USB-devices boot up. FDD/ODD/HDD/SuperDrive???? I don't know what the last one means, but it by *force* still has got autodetection which doesn't work. It always says my USB-stick is HDD no matter if it is empty, FDD-formatted, CD-formatted or the most logical one - FAT32 (like HDD) formatted.
But still no booting - the familiar "operating system missing".

I'll replace my current Core 2 with Intel soon so I can post you some more feedback.

EDIT:
I just tried that HP utility and weird thing happen as always with HP. That utility needs your lock to be unlocked if you have it...WAIT!...let me rephrase that: you MUST have that lock switch to even USE this program. The USB-stick that doesn't have this lock-switch is ALWAYS locked to this program. Okay, past that, I managed to put my files on the USB with that utility and it miraculously booted.

Does this mean that HP BIOSs always check for some trace of their own programs so that you can't boot any other signatures? If so, then WHY?