diff --git a/hitl/loopback.py b/hitl/loopback.py
index 679d2b7..475cd63 100644
--- a/hitl/loopback.py
+++ b/hitl/loopback.py
@@ -12,7 +12,7 @@ import sys
 from gmqtt import Client as MqttClient
 from miniconf import Miniconf
 
-# The minimum allowably loopback voltage error (difference between output set point and input
+# The minimum allowable loopback voltage error (difference between output set point and input
 # measured value).
 MINIMUM_VOLTAGE_ERROR = 0.010
 
@@ -52,34 +52,30 @@ class TelemetryReader:
     """ Helper utility to read Stabilizer telemetry. """
 
     @classmethod
-    async def create(cls, prefix, broker):
+    async def create(cls, prefix, broker, queue):
         """Create a connection to the broker and an MQTT device using it."""
         client = MqttClient(client_id='')
         await client.connect(broker)
-        return cls(client, prefix)
+        return cls(client, prefix, queue)
 
 
-    def __init__(self, client, prefix):
+    def __init__(self, client, prefix, queue):
         """ Constructor. """
         self.client = client
         self._telemetry = []
         self.client.on_message = self.handle_telemetry
         self._telemetry_topic = f'{prefix}/telemetry'
         self.client.subscribe(self._telemetry_topic)
+        self.queue = queue
 
 
     def handle_telemetry(self, _client, topic, payload, _qos, _properties):
         """ Handle incoming telemetry messages over MQTT. """
         assert topic == self._telemetry_topic
-        self._telemetry.append(json.loads(payload))
+        self.queue.put_nowait(json.loads(payload))
 
 
-    def get_latest(self):
-        """ Get the latest telemetry message received. """
-        return self._telemetry[-1]
-
-
-async def test_loopback(miniconf, telemetry, set_point):
+async def test_loopback(miniconf, telemetry_queue, set_point, gain=1, channel=0):
     """ Test loopback operation of Stabilizer.
 
     Note:
@@ -91,24 +87,27 @@ async def test_loopback(miniconf, telemetry, set_point):
         miniconf: The miniconf configuration interface.
         telemetry: a helper utility to read inbound telemetry.
         set_point: The desired output voltage to test.
+        channel: The loopback channel to test on. Either 0 or 1.
+        gain: The desired AFE gain.
     """
-    print(f'Testing loopback for Vout = {set_point:.2f}')
+    print(f'Testing loopback for Vout = {set_point:.2f}, Gain = x{gain}')
     print('---------------------------------')
-    # Configure the IIRs to output at the set point
-    await miniconf.command('iir_ch/0/0', static_iir_output(set_point), retain=False)
-    await miniconf.command('iir_ch/1/0', static_iir_output(set_point), retain=False)
-    await miniconf.command('telemetry_period', 1, retain=False)
+    # Configure the AFE and IIRs to output at the set point
+    await miniconf.command(f'afe/{channel}', f'G{gain}', retain=False)
+    await miniconf.command(f'iir_ch/{channel}/0', static_iir_output(set_point), retain=False)
 
-    # Wait for telemetry values to update.
+    # Configure signal generators to not affect the test.
+    await miniconf.command('signal_generator/0/amplitude', 0, retain=False)
+
+    # Wait for telemetry to update.
     await asyncio.sleep(5.0)
 
     # Verify the ADCs are receiving the setpoint voltage.
     tolerance = max(0.05 * set_point, MINIMUM_VOLTAGE_ERROR)
-    latest_values = telemetry.get_latest()
+    latest_values = await telemetry_queue.get()
     print(f'Latest telemtry: {latest_values}')
 
-    assert abs(latest_values['adcs'][0] - set_point) < tolerance
-    assert abs(latest_values['adcs'][1] - set_point) < tolerance
+    assert abs(latest_values['adcs'][channel] - set_point) < tolerance
     print('PASS')
     print('')
 
@@ -123,22 +122,38 @@ def main():
 
     args = parser.parse_args()
 
+    telemetry_queue = asyncio.LifoQueue()
+
+    async def telemetry():
+        await TelemetryReader.create(args.prefix, args.broker, telemetry_queue)
+        try:
+            while True:
+                await asyncio.sleep(1)
+        except asyncio.CancelledError:
+            pass
+
+
+    telemetry_task = asyncio.Task(telemetry())
+
     async def test():
         """ The actual testing being completed. """
         interface = await Miniconf.create(args.prefix, args.broker)
-        telemetry = await TelemetryReader.create(args.prefix, args.broker)
+
+        # Disable IIR holds and configure the telemetry rate.
+        await interface.command('allow_hold', False, retain=False)
+        await interface.command('force_hold', False, retain=False)
+        await interface.command('telemetry_period', 1, retain=False)
 
         # Test loopback with a static 1V output of the DACs.
-        await test_loopback(interface, telemetry, 1.0)
+        await test_loopback(interface, telemetry_queue, 1.0)
 
         # Repeat test with AFE = 2x
-        print('Configuring AFEs to 2x input')
-        await interface.command('afe/0', "G2", retain=False)
-        await interface.command('afe/1', "G2", retain=False)
-        await test_loopback(interface, telemetry, 1.0)
+        await test_loopback(interface, telemetry_queue, 1.0, gain=2)
 
         # Test with 0V output
-        await test_loopback(interface, telemetry, 0.0)
+        await test_loopback(interface, telemetry_queue, 0.0)
+
+        telemetry_task.cancel()
 
     loop = asyncio.get_event_loop()
     sys.exit(loop.run_until_complete(test()))
diff --git a/hitl/run.sh b/hitl/run.sh
index e3a86dc..7c7aa27 100755
--- a/hitl/run.sh
+++ b/hitl/run.sh
@@ -15,7 +15,7 @@ python3 -m venv --system-site-packages py
 . py/bin/activate
 
 # Install Miniconf utilities for configuring stabilizer.
-python3 -m pip install git+https://github.com/quartiq/miniconf#subdirectory=miniconf-py
+python3 -m pip install git+https://github.com/quartiq/miniconf#subdirectory=py/miniconf-mqtt
 python3 -m pip install gmqtt
 
 cargo flash --chip STM32H743ZITx --elf target/thumbv7em-none-eabihf/release/dual-iir