I am having the exact same problem. I am running 2021110200, which used to be running perfectly. I haven't been playing it for a while. When I tried to run it today, e-amu card and insert coin button both were not working.
Here's more info on my end: changed spec type H to G, valkyrie laser effects are not displayed correctly. The main screen/L2D is 120fps, but the gameplay seems to be 60fps (the ingame fps counter says 120fps). I am not experiencing any sound problem though.