Yes.  Based on your description and if you attempted to plug a monitor via HDMI and get a rainbow screen, it means something is wrong with your image.  

We have actually created a NEW version of the Sigma Tile image with new code.   I will be publishing the information about this shortly... However, in the meantime, you can use the following link to get this latest disk image:

https://drive.google.com/open?id=1B1PaztKs3maJ3gNjGcUymXSaM_k6HTZd