Yeah, I only thought that input-switching halfway through. Sorry about that (I had my 669 on HDMI but I have adapters on the PC side so I was converting DVI to HDMI at first before I got the long HDMI/USB cable). Besides, if it's flickering with the B.U. Cam input too (which I also managed to pass over) then it wouldn't be a MOBO video out issue.
If it was fine with the Wall Supply and not fine with the M4, that would imply that "the M4 is bad" but if it runs your pc, it may just be that the Lilly doesn't like the output ripple from the M4 (presuming that there is some ripple).