OMG - I FINALLY got the I2C to the HDMI re-drivers working. I took an hour off to go watch the fireworks and then came back and locked in.

There were two main issues. First the MUX needed > 2.5v. Secondly, the EN pins had a 250k internal pull up, but when I measured them they were 0V. It turns out I tied them to extra FPGA pins in case I wanted to control them. The FPGA was uninitialized and pulling them down.

Then I had one of the addresses wrong. But finally, the thing that should be UBER simple to get working, is working.

I'll try configuring them tomorrow and see if I get a HDMI signal out of them.