HDMI handshake problem only after jailbreak

Hi, I'm fairly new to jailbreaking so excuse me if I dont have all the info you may need right off the bat.

I had been borrowing an atv2 running 4.1.1 to make sure it would fit my needs.  Everything was great, I ran the HDMI to my Sony reciever then HDMI out to my projector.

After purcasing my own atv2 (running 4.2.1 2100), i plugged it in right out of the box to make sure the hardware was in working order, everything was fine.

Jailbroke using seas0npass, and after the apple logo on boot, i get no video, i can ssh into the box, run apt-get update etc so i know its booting untethered.

Resored to the backup ipsw, everything works again.  Tried greepois0n, same results, tried pwnagetool, same results. I decided to try jailbreaking from a different mac and before i got that far it was working great on the computer monitor, installed xbmc and updated everything. Yay, working flawlessly. Back to the living room and I get the same problem again.

Turns out that afterjailbreaking if i run the HDMI thru my receiver the video fails, if i run it straight to the projector I get video just fine.

I've mamanged to find a handful of items mentioning HDMI handshake problems with the most recent iOS, but nothing difinitive or new.

My setup really doent allow for me to have the atv2 as the only hdmi device, is there anything i can do to fix this HDMI issue?