diff --git a/esp_idf_size/main.py b/esp_idf_size/main.py
index 13bfa9d..b44289f 100644
--- a/esp_idf_size/main.py
+++ b/esp_idf_size/main.py
@@ -49,6 +49,8 @@ def main() -> None:
         prog='esp_idf_size', description='This tool displays firmware size information for project built by ESP-IDF'
     )
 
+    parser.add_argument('--ng', action='store_true', help="stub for 1.x compat")
+
     parser.add_argument(
         'input_file', metavar='MAP_FILE', help='Path to the link map file generated by the ESP-IDF build system.'
     )