Fair enough. I'll wear my sarcasm bells much more obviously next time to you can hear me coming from miles away
USB flashback has nothing to do with being able to flash without a CPU. What it does is enable flashing of the BIOS with minimal power settings so that you don't have to boot in order to do it. But this is far and away from flashing using an empty socket. Minimal power and empty sockets are very different things, MPC got it wrong, and should not trust that writer more than the manual.
No board to date is able to function without the CPU, as said board would need a mind of it's own. So hit that button all you want...it ain't doing jack. Gigabyte nor Asus say they can flash without a CPU...MPC editors did. The manual doesn't lie.