diff --git a/scripts/west/zap_append.py b/scripts/west/zap_append.py
index 5ac740e3a2..549dd5945d 100644
--- a/scripts/west/zap_append.py
+++ b/scripts/west/zap_append.py
@@ -12,6 +12,15 @@
 from zap_common import DEFAULT_MATTER_PATH, DEFAULT_MATTER_TYPES_RELATIVE_PATH, DEFAULT_ZCL_JSON_RELATIVE_PATH
 
 
+def get_attribute_name(attribute: ET.Element) -> str:
+    """If attribute has a name, return it, otherwise fallback to the text of the attribute entry."""
+    from_attr = attribute.get('name')
+    if from_attr:
+        return from_attr
+    text = ''.join(attribute.itertext()).strip()
+    return text or None
+
+
 def add_custom_attributes_from_xml(xml_file: Path, zcl_data: dict, matter_path: Path = DEFAULT_MATTER_PATH):
     """
     Parse the cluster XML file and add attributes with custom types to
@@ -50,7 +59,7 @@ def add_custom_attributes_from_xml(xml_file: Path, zcl_data: dict, matter_path:
         # Check all attributes in the cluster
         for attribute in cluster.findall('attribute'):
             attr_type = attribute.get('type')
-            attr_name = attribute.get('name')
+            attr_name = get_attribute_name(attribute)
 
             if attr_type and attr_type not in types:
                 attributes_with_missing_types.append({
diff --git a/scripts/west/zap_common.py b/scripts/west/zap_common.py
index 8585b307c6..e6c973443a 100644
--- a/scripts/west/zap_common.py
+++ b/scripts/west/zap_common.py
@@ -299,13 +299,18 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 
 def display_zap_message(output: subprocess.CompletedProcess[str]) -> None:
     """
-    If the output contains the error from napi_throw, suggest user to use zap-sync to sync the ZAP file.
+    If the output contains the error from napi_throw, suggest user to use zap-sync to sync the ZAP file and make sure that all attributes are provided.
     """
+    if output.stdout:
+        log.dbg(f"output: {output.stdout}")
+
+    if output.stderr:
+        log.wrn(f"stderr: {output.stderr}")
+
     if 'Unknown attribute' in output.stdout:
-        log.err("Your zcl.json file seems to be outdated. Please use 'west zap-sync' command to synchronize it with the newest Matter Data Model.")
-        return
-    else:
-        print(f"output: {output.stdout}")
+        log.err("Your zcl.json file seems to be outdated or is missing some attributes. "
+                "Please use 'west zap-sync' command to synchronize it with the newest Matter Data Model "
+                "and make sure that all cluster attributes are properly defined in the cluster XML file.")
 
 
 class ZapInstaller:
diff --git a/scripts/west/zap_gui.py b/scripts/west/zap_gui.py
index 34588689e9..b1b9e4a845 100644
--- a/scripts/west/zap_gui.py
+++ b/scripts/west/zap_gui.py
@@ -102,6 +102,10 @@ def run_zap():
                     cmd += ["--tempState"]
 
                 output = subprocess.run([str(x) for x in cmd], capture_output=True, text=True)
+                # Chromium often prints nothing to stdout when the sandbox aborts early.
+                # returncode -5 is a sentinel consumed by fix_sandbox_permissions().
+                if output.returncode != 0 and not output.stdout and not output.stderr:
+                    raise subprocess.CalledProcessError(-5, cmd)
                 display_zap_message(output)
                 return output
 
diff --git a/scripts/west/zap_sync.py b/scripts/west/zap_sync.py
index 753694c5e3..db8ace920e 100644
--- a/scripts/west/zap_sync.py
+++ b/scripts/west/zap_sync.py
@@ -56,13 +56,17 @@ def do_run(self, args, unknown_args):
         zap_installer.update_zap_if_needed()
 
         if args.zcl_json:
-            # Provided zcl.json file exists, so we need to remove it and create a copy of the default zcl.json file.
-            zcl_file_path = Path(args.zcl_json).absolute()
-            if zcl_file_path.exists():
-                zcl_file_path.unlink()
-            shutil.copy(default_zcl_path, zcl_file_path)
+            zcl_candidate = Path(args.zcl_json).absolute()
+            # Reset project zcl.json from the SDK default. If -j is the default path itself,
+            # do not unlink/copy (to avoid deleting the source then failing to copy if the path is the same).
+            if zcl_candidate.resolve() == default_zcl_path.resolve():
+                zcl_file_path = default_zcl_path
+            else:
+                if zcl_candidate.exists():
+                    zcl_candidate.unlink()
+                shutil.copy(default_zcl_path, zcl_candidate)
+                zcl_file_path = zcl_candidate
         else:
-            # No zcl.json file provided, so we need to create a new one because a path was provided.
             zcl_file_path = default_zcl_path
 
         log.inf(f"Synchronizing zcl.json file ({zcl_file_path.resolve()})...")
@@ -91,6 +95,10 @@ def run_zap():
             cmd += ["--tempState"]
 
             output = subprocess.run([str(x) for x in cmd], capture_output=True, text=True)
+            # Chromium often prints nothing to stdout when the sandbox aborts early.
+            # returncode -5 is a sentinel consumed by fix_sandbox_permissions().
+            if output.returncode != 0 and not output.stdout and not output.stderr:
+                raise subprocess.CalledProcessError(-5, cmd)
             display_zap_message(output)
             return output