The HP t5570 has a standard AMI BIOS - hit F10 on power-up to get into the BIOS setup screen.
The first/second/third Boot Devices can be set to:
This is essentially USB, HDD or Network. I guess the BIOS tacks on a physical description of what it finds.
I tried adding a SATA DOM. It was found and reported on the Standard CMOS Features screen, but was not added to the boot options in the Advanced BIOS Features screen.
With the USB option set it booted Linux distributions from a Pen Drive without any problems.
My t5570 came with Windows Embedded Standard 2009.