I've successfully transitioned my massively modified shapeoko 2 over to a Tinyg controller. So far I've really loved the combo. I've had some issues with TGFX, but the controller seems to run perfectly. I originally had my limit switches set up in NO mode, and as such my touch plate connected to A min worked great for running g38.2 probe cycles to set the work coordinate z zero for the current tool.
I changed the switches over to NC mode for better noise isolation, though, and now running a g38.2 command doesn't even get the z axis moving. I read somewhere that the g38.2 command works regardless of whether the limit switches are in NC or NO mode, but that doesn't seem to be the case for me.
I think you have to temporarily change over to NO for G38.2. This should probably be logged as an issue on github. Do you remember where you read that NO and NC are OK? I dpn't recall this, and if it;s out there I'd like to correct it. -- Thanks.