Modifying an HDMI dummy plug’s EDID using a Raspberry Pi (opens in new tab)

I recently found myself needing to change the monitor that a cheap HDMI “dummy plug” pretended to be. It was a random one I had bought on Amazon several years ago that acted as a 4K monitor, and I needed it to be something simpler that didn’t support a 4K resolution. The story behind why is a long one that I’m still figuring out and might eventually become a separate blog post in the future.