[xubuntu] Unable to boot from USB ASRock FM285X Extreme6 Mobo

Hi all, I'm trying to boot into a USB Xubuntu install on my rig with the titular mobo. I'm using 2 Sandisk Cruzer 8 GB sticks (1 with the installation media via unetbootin and 1 to serve as HD). However when I attempt to boot in the Power/Reset/Dr. Debug LEDs shut off and the display loses signal within a few seconds. However, the board still seems to receive power. I've tried placing the stick in both USB 2.0 and 3.0 slots to no avail.

Parts:
AMD A4 5300
Sapphire HD 7950 Vapor-X
Crucial Ballistix 8 GB
No HDD or CD/DVD drive

Here's a video illustrating the problem: http://www.youtube.com/watch?v=ezd0gfsyCO8

Thanks in advance.