The Geeetechs come with their own firmware, and i'm on the latest version of that. I think i might have been having trouble with binding on the Z axix. I have pulled the threaded rod out and made it a little straighter. I ran a die down it, but it was clean. Put a tap through the nut and it was a little tight so its been cleaned out now. Then ran the nut all the way down the rod and it was very smooth.