diff --git a/api/src/opentrons/hardware_control/backends/ot3controller.py b/api/src/opentrons/hardware_control/backends/ot3controller.py
index 3b15a66e318..eced853b962 100644
--- a/api/src/opentrons/hardware_control/backends/ot3controller.py
+++ b/api/src/opentrons/hardware_control/backends/ot3controller.py
@@ -1151,7 +1151,7 @@ async def watch(self, loop: asyncio.AbstractEventLoop) -> None:
     def axis_bounds(self) -> OT3AxisMap[Tuple[float, float]]:
         """Get the axis bounds."""
         # TODO (AL, 2021-11-18): The bounds need to be defined
-        phony_bounds = (0, 10000)
+        phony_bounds = (0, 500)
         return {
             Axis.Z_L: phony_bounds,
             Axis.Z_R: phony_bounds,
diff --git a/api/src/opentrons/hardware_control/ot3api.py b/api/src/opentrons/hardware_control/ot3api.py
index 36509e7fb8d..57f4e2d8efc 100644
--- a/api/src/opentrons/hardware_control/ot3api.py
+++ b/api/src/opentrons/hardware_control/ot3api.py
@@ -653,10 +653,11 @@ async def cache_instruments(
         Scan the attached instruments, take necessary configuration actions,
         and set up hardware controller internal state if necessary.
         """
-        skip_configure = await self._cache_instruments(require)
-        if not skip_configure or not self._configured_since_update:
-            self._log.info("Reconfiguring instrument cache")
-            await self._configure_instruments()
+        async with self._motion_lock:
+            skip_configure = await self._cache_instruments(require)
+            if not skip_configure or not self._configured_since_update:
+                self._log.info("Reconfiguring instrument cache")
+                await self._configure_instruments()
 
     async def _cache_instruments(  # noqa: C901
         self, require: Optional[Dict[top_types.Mount, PipetteName]] = None
@@ -676,11 +677,11 @@ async def _cache_instruments(  # noqa: C901
             # We should also check version here once we're comfortable.
             if not pipette_load_name.supported_pipette(name):
                 raise RuntimeError(f"{name} is not a valid pipette name")
-        async with self._motion_lock:
-            # we're not actually checking the required instrument except in the context
-            # of simulation and it feels like a lot of work for this function
-            # actually be doing.
-            found = await self._backend.get_attached_instruments(checked_require)
+
+        # we're not actually checking the required instrument except in the context
+        # of simulation and it feels like a lot of work for this function
+        # actually be doing.
+        found = await self._backend.get_attached_instruments(checked_require)
 
         if OT3Mount.GRIPPER in found.keys():
             # Is now a gripper, ask if it's ok to skip
@@ -726,7 +727,7 @@ async def _cache_instruments(  # noqa: C901
     async def _configure_instruments(self) -> None:
         """Configure instruments"""
         await self.set_gantry_load(self._gantry_load_from_instruments())
-        await self.refresh_positions()
+        await self.refresh_positions(acquire_lock=False)
         await self.reset_tip_detectors(False)
         self._configured_since_update = True
 
@@ -983,9 +984,11 @@ async def current_position_ot3(
             OT3Mount.from_mount(mount), self._current_position, critical_point
         )
 
-    async def refresh_positions(self) -> None:
+    async def refresh_positions(self, acquire_lock: bool = True) -> None:
         """Request and update both the motor and encoder positions from backend."""
-        async with self._motion_lock:
+        async with contextlib.AsyncExitStack() as stack:
+            if acquire_lock:
+                await stack.enter_async_context(self._motion_lock)
             await self._backend.update_motor_status()
             await self._cache_current_position()
             await self._cache_encoder_position()