Problems Recording Retron 5

[StuffWePlay]

I recently decided to purchase a Retron 5 for use while retro games while I am attending college. I have been using a Blackmagic Intensity Shuttle Thunderbolt as my capture card with my 2011 iMac, and its been working great so far with all of my other consoles. The Retron works fine when it is plugged into the tv directly and not through the capture card. However, whenever I plug the Retron into it, the screen starts flickering rapidly and the audio becomes sped up and high pitched.
I have tried different HDMI cables and outputting to a different tv but nothing has worked. I tried the capture card with different consoles again (notably my 360, my Wii U, and my Gamecube through an upscaler) and those all work just fine and record smoothly with no audio problems at the highest settings.
This has been frustrating me for several days now. I am tempted to return the console if I can not solve this, as the main reason I got it was so that I can still create content for my youtube channels while at college. I greatly appreciate any help that can be offered!

[AaronC]

Have you tried the new firmware?

I've had mine since Christmas last year and it has worked great for me. I'm using a Macbook Pro with the Happauge (sp?) HD capture device. I did have an issue with my PS3 because of some HDCP passthrough issues, but that is about it.

Hope you can get fixed. I work in the consumer electronics world and my first two questions are always "Is it plugged in?" and "Did you run the new firmware update?" Haha!

[StuffWePlay]

I just updated the Retron to the newest firmware. While the system itself loads games and boots up faster now, which is good, it is still unusable with my capture card, as I am still having the rapid screen flickering and the high pitched audio when it is connected to it.
And I can understand that. Its all good

[JGBtypeR]

I don't really have any sound reasoning but maybe you could throw an hdmi splitter in there?

I've got this one: https://www.amazon.com/dp/B0089DSLMY that I've used to strip the hdcp from my pstv and have also ran my retron through it with no issues. Maybe it's something with the hdmi handshake (though I think that's usually only with hdcp stuff).

[StuffWePlay]

EDIT: I ended up returning the Retron. After trying it with a friend's Elgato game capture and having a similar issue, I decided that the machine was too much of a problem child, located my receipt, and returned it. On the bright side, I used the money I got from returning it to buy my gf a new 3DS, so at least some good came out of all of this. I appreciate everyone's help!