Gound Fault when HDMI is connected

This devices continues to not impress. With some displays it does not make it into the desktop (especially 4k ones). But what they all have in common that I have to connect the GND UART pin to a Serial Interface for them to even boot up at all. It does not even need to be connected to Laptop, I plugged it right into the same Anker 87W Battery (Serial, Radxa and USB powered Monitor). I can also plug the Serial Interface into a Laptop with it’s own Battery for it to boot. There also seems to be a low voltage potential of (~0.7V) on the 5V line when HDMI with a powered is connected but the Radxa is not powered up.

I am wondering if all those issues (including the Wifi) is caused by a Hardware design issue with the power and grounding.

You mean the Radxa Zero, right?