diff --git a/src/py/bbctrl/Mach.py b/src/py/bbctrl/Mach.py
index a522a00..1eead51 100644
--- a/src/py/bbctrl/Mach.py
+++ b/src/py/bbctrl/Mach.py
@@ -371,12 +371,9 @@ class Mach(Comm):
 
             # Set the absolute position both locally and via the AVR
             target = position + state.get('offset_' + axis)
-            json_data = config.copy()
-            axes = json_data.get('axes')
-            if axes:
-                json_data['axes'][axis] = { "abs": target, "off": state.get('offset_' + axis) }
-            else:
-                json_data['axes'] = { axis: { "abs": target, "off": state.get('offset_' + axis) } }
+            json_data = config.values.copy()
+            axes = json_data.setdefault('axes', {})
+            axes[axis] = { 'abs' : target, 'off' : state.get('offset_' + axis)}
             config.save(json_data)
             state.set(axis + 'p', target)
             super().queue_command(Cmd.set_axis(axis, target))