I've just gotten my Geeetech A10. I have a 3dTouch sensor installed. I got my offset and calibration set.
If I send a G1 or G0 command, regardless of arguments, it runs the print head off the front left of the bed [0,-6, 0]. I can send a G28 and it returns to the middle of the bed pretty much as expected.
For instance - I send G0 X10 Y10, it still runs to that same [0,-6, 0] position. Attempting to print anything is a no-go because every G1 or G0 sends it running back to that spot to spit filament off the edge of the bed.
I've rebuilt firmware from Geeetech's linked sources twice. Everything works with control from the dial, it just doesn't interpret G-code in any useful way.