Changing the boot device from PXE to hard disk

[Javier Martín Rueda]

I have set up a simple unattended installation system for FreeBSD, so 
that I can manually configure a group of computers to boot with PXE, and 
when they boot they will automatically install FreeBSD.

The final step would be to configure the BIOS to boot from the first 
hard drive. So far I can do that manually by pressing "Del" when the 
computer boots and entering the ROM BIOS setup program, but I would like 
to know if it is possible somehow to change the boot device priority in 
the BIOS from FreeBSD?