I just installed a NESRGB-igr in a AV-Famicom and ran into this same problem, and I found that it will work if you start the console with the controller unplugged, and then press the reset button, after that you can plug the controller back in, and everything seems to work just fine. I have an NESRGB 2.0, and one of the newer N8 Pros with the 3.3v jumper. All of my real game carts that I have tested don't have this problem, just the Everdrive N8 Pro.