Howto modify BIOS setting without reboot ?
 

Is there a utility that allows me to change my BIOS boot order to net boot without user intervention ?

I have a bunch of machines running various Linux distributions. All are booted from hard disk. I need to pxe boot all of them, but do not want to go and manually change the boot order in BIOS. Any help would be appreciated.

You might be able to find a utility that could read, modify, and re-write the BIOS for you, but it would need to be BIOS specific. I'm not aware of any such program in existence: I'm not even sure if userspace can READ the flash memory of the BIOS.