diff --git a/9_Firmware/9_3_GUI/requirements_v7.txt b/9_Firmware/9_3_GUI/requirements_v7.txt
index 0a5ea08..72f9db3 100644
--- a/9_Firmware/9_3_GUI/requirements_v7.txt
+++ b/9_Firmware/9_3_GUI/requirements_v7.txt
@@ -17,6 +17,3 @@ scipy>=1.10
 # Tracking / clustering (optional)
 scikit-learn>=1.2
 filterpy>=1.4
-
-# CRC validation (optional)
-crcmod>=1.7
diff --git a/9_Firmware/9_3_GUI/v7/hardware.py b/9_Firmware/9_3_GUI/v7/hardware.py
index b9b4109..d855a4b 100644
--- a/9_Firmware/9_3_GUI/v7/hardware.py
+++ b/9_Firmware/9_3_GUI/v7/hardware.py
@@ -32,10 +32,23 @@ def _load_radar_protocol():
     if mod_name in sys.modules:
         return sys.modules[mod_name]
     proto_path = pathlib.Path(__file__).resolve().parent.parent / "radar_protocol.py"
+    if not proto_path.is_file():
+        raise FileNotFoundError(
+            f"radar_protocol.py not found at expected location: {proto_path}"
+        )
     spec = importlib.util.spec_from_file_location(mod_name, proto_path)
+    if spec is None or spec.loader is None:
+        raise ImportError(
+            f"Cannot create module spec for radar_protocol.py at {proto_path}"
+        )
     mod = importlib.util.module_from_spec(spec)
+    # Register before exec so cyclic imports resolve correctly, but remove on failure
     sys.modules[mod_name] = mod
-    spec.loader.exec_module(mod)  # type: ignore[union-attr]
+    try:
+        spec.loader.exec_module(mod)
+    except Exception:
+        sys.modules.pop(mod_name, None)
+        raise
     return mod
 
 
diff --git a/9_Firmware/9_3_GUI/v7/workers.py b/9_Firmware/9_3_GUI/v7/workers.py
index c467c98..4e491a0 100644
--- a/9_Firmware/9_3_GUI/v7/workers.py
+++ b/9_Firmware/9_3_GUI/v7/workers.py
@@ -131,6 +131,10 @@ class RadarDataWorker(QThread):
         self._byte_count = 0
         self._error_count = 0
 
+        # Monotonically increasing target ID — persisted across frames so map
+        # JS can key markers/trails by a stable ID.
+        self._next_target_id = 0
+
     def stop(self):
         self._running = False
         if self._acquisition:
@@ -244,7 +248,7 @@ class RadarDataWorker(QThread):
                 )
 
             target = RadarTarget(
-                id=len(targets),
+                id=self._next_target_id,
                 range=range_m,
                 velocity=velocity_ms,
                 azimuth=azimuth,
@@ -254,6 +258,7 @@ class RadarDataWorker(QThread):
                 snr=snr,
                 timestamp=frame.timestamp,
             )
+            self._next_target_id += 1
             targets.append(target)
 
         # DBSCAN clustering