Doing Filament Change Command (M600) using limit switches

[Roxy]

edit: Oh, I almost forgot but I use a Ramps 1.4 board and I am not even sure what that board was/is in your write up/post.

I wish I had a RAMPS board, but I have a PrintrBoard. However, that really doesn't matter. You just need to find an unused GPIO pin on your board and wire a switch to it (and declare that pin for use by the firmware). It is pretty straight forward to check if you have the switch wired up correctly. If you decide to do that, I'll help you get the M600 code working on your board.