I use an APU, but with any netboot small computer, I find it easier to netboot a simple linux build and dd the image via netcat, vs plugging and unplugging the card.

My notes for pfsense: receiving machine: netcat -l 2222 | gzip -dc | dd of=/dev/sda

sending machine: dd if=pfSense-2.2.4-RELEASE-2g-i386-nanobsd.img.gz |netcat 10.10.10.101 2222