I am trying to install FreeNAS on a Dell PowerEdge T320. I've followed the instructions here (http://doc.freenas.org/index.php/Burning_an_IMG_File) to write the .img file to four different USB sticks with dd if=FreeNAS-9.2.1.5-RELEASE-x64.img of=/dev/sde, but I can't boot off of any of them. When I try to boot, I get the following screen:

F1 FreeBSD
F2 FreeBSD
F3 Drive 0

Then it auto-selects F1 and either prints # about once a second forever, or it sits with a blinking cursor doing nothing.

Forum posts and the wiki page linked above say to set the USB boot emulation mode to hard disk (as opposed to auto or CD/DVD/floppy), and older Dell PowerEdge models including the T310 have this option in the BIOS settings, but I cannot find it on the T320 with the latest BIOS 2.1.2.

I have even tried writing the USB image to a USB hard disk, but with the same lack of success.

Has anyone been able to find this USB boot setting on a T320, or been able to boot FreeNAS/FreeBSD from USB in some other way on a T320?