diff --git a/src/python/devtest/os/test/ListCmd.py b/src/python/devtest/os/test/ListCmd.py
index 24e46d6..1aa9b70 100644
--- a/src/python/devtest/os/test/ListCmd.py
+++ b/src/python/devtest/os/test/ListCmd.py
@@ -355,17 +355,24 @@ class ListCmd(TestCase): # export
         slog_m(NOTICE, "--- ignored:\n", format_rows(ignored))
 
         r = []
+        sep = ', '
+        line_break = ''
+        and_str = ' and '
+        if (len(missing) > 3 or len(too_many) > 3):
+            sep = ',\n'
+            line_break = '\n'
+            and_str = '\n'
         if len(missing):
             slog_m(ERR,    "--- should be there but are not:\n", format_rows(missing, quotes=True))
-            r.append("missing:" + ', '.join([row.name for row in missing]))
+            r.append("missing:" + line_break + sep.join([row.name for row in missing]))
         if len(too_many):
             slog_m(ERR,    "--- too many:\n", format_rows(too_many, quotes=True))
-            r.append("too many: " + ', '.join([row.name for row in too_many]))
+            r.append(line_break + "too many: " + line_break + sep.join([row.name for row in too_many]))
         if not len(r):
             return None
 
-        feature_diff = set(features) - last_features
-        if self.__write_response and len(feature_diff):
+        if self.__write_response and (len(missing) or len(too_many)):
+            feature_diff = set(features) - last_features # if len(feature_diff) ?
             response_path = self.refpath[0] + '.bad'
             if tstamp is not None:
                 response_path += '-' + tstamp
@@ -377,12 +384,13 @@ class ListCmd(TestCase): # export
                 if len(missing):
                     f.write("# --- missing {}\n".format(feature_diff))
                     for row in missing:
-                        f.write(row.line.strip() + ' # "needed": [{}], "bad": ["default"]\n'.format(feature_diff_str))
+                        f.write(row.line.strip() + ' # "bad": [{}]\n'.format(feature_diff_str))
                 if len(too_many):
                     f.write("# --- too many {}\n".format(feature_diff))
                     for row in too_many:
-                        f.write(row.line.strip() + ' # "bad" [{}]\n'.format(feature_diff_str))
-        return ' and '.join(r)
+                        f.write(row.line.strip() +
+                                ' # "needed": [{}], "bad": ["default"]\n'.format(feature_diff_str))
+        return and_str.join(r)
 
     async def _run(self, env, machine, phase):
         console   = get_console(env)