How to use Digilent rgb2dvi correctly?

I am trying to make a simple design that streams out RGB 24 bit data, and outputs it out on HDMI. However I don’t get anything on the display.

here is the block design
bd.pdf (92.0 KB)

clock wizard generates 40 MHZ. for 800 x 600.
same is reflected in default section of VTC.
RGB2DVI is set for less than 80 MHz, with serial clock generated internally from pixel clock.

The video patters generator is a very simple IP that streams out colour bars, written in hls. This was working with ZEDboard. I have generated a new project for hls, with xc7z020clg400-1 part number just to be safe.

How should I troubleshoot it?