I've been using an HDMI dongle for one of my PS2s to upscale the text and graphics for better enjoyment on my HD tv. I loved the performance so much that I decided to embed it inside the PS2 to fully commit to it and to get back to the normal footprint of the PS2 as the dongle stuck out a lot making the PS2 stick out that much more on my already cramped work bench. This also frees up the AV port thus eliminating the need to remove the dongle and switch back to the AV cable when needed.
This was accomplished by finding out where the dongle connects to the PS2s AV port and recreating those connections with a hard wired ribbon cable. After the connections were mapped I had to find a spot to mount the dongle in the PS2. The space is limited but there was just enough next to the ethernet port. A few modifications were made to accommodate the dongle but they were well worth it. The dongle also requires a 5volt power source which I hard wired to the USB ports 5 volt output.