If you register for the MEAU website, you can download a plethora of information. Inside that, you'll find how to access the user and machine parameters. Unfortunately, Mitsubishi restricts information on the System parameters. You won't find how to access it inside their manuals because this is where you can do things like adding an extra axis, turn on contouring, etc. Many of these things are features that I believe Mitsubishi may indirectly (or possibly directly) sells through the integrator. Don't quote me on that... All I know is that the won't help you at all with true system level parameters. However, I know that on the M3 controls the dump is "in the clear" so you could modify the params, if you know what the values should be (again, nothing is documented there).

I could help you with an M3, but the M64 has a different password to get into the System area. I don't know what that is... Sorry.