diff --git a/src/wps/wps_dev_attr.c b/src/wps/wps_dev_attr.c
index 6ae84f262..823c7ef51 100644
--- a/src/wps/wps_dev_attr.c
+++ b/src/wps/wps_dev_attr.c
@@ -25,18 +25,20 @@ int wps_build_manufacturer(struct wps_device_data *dev, struct wpabuf *msg)
 	wpa_printf(MSG_DEBUG, "WPS:  * Manufacturer");
 	wpabuf_put_be16(msg, ATTR_MANUFACTURER);
 	len = dev->manufacturer ? os_strlen(dev->manufacturer) : 0;
+#ifndef CONFIG_WPS_STRICT
 	if (len == 0) {
 		/*
 		 * Some deployed WPS implementations fail to parse zero-length
-		 * attributes. As a workaround, send a null character if the
+		 * attributes. As a workaround, send a space character if the
 		 * device attribute string is empty.
 		 */
 		wpabuf_put_be16(msg, 1);
-		wpabuf_put_u8(msg, '\0');
-	} else {
-		wpabuf_put_be16(msg, len);
-		wpabuf_put_data(msg, dev->manufacturer, len);
+		wpabuf_put_u8(msg, ' ');
+		return 0;
 	}
+#endif /* CONFIG_WPS_STRICT */
+	wpabuf_put_be16(msg, len);
+	wpabuf_put_data(msg, dev->manufacturer, len);
 	return 0;
 }
 
@@ -47,18 +49,20 @@ int wps_build_model_name(struct wps_device_data *dev, struct wpabuf *msg)
 	wpa_printf(MSG_DEBUG, "WPS:  * Model Name");
 	wpabuf_put_be16(msg, ATTR_MODEL_NAME);
 	len = dev->model_name ? os_strlen(dev->model_name) : 0;
+#ifndef CONFIG_WPS_STRICT
 	if (len == 0) {
 		/*
 		 * Some deployed WPS implementations fail to parse zero-length
-		 * attributes. As a workaround, send a null character if the
+		 * attributes. As a workaround, send a space character if the
 		 * device attribute string is empty.
 		 */
 		wpabuf_put_be16(msg, 1);
-		wpabuf_put_u8(msg, '\0');
-	} else {
-		wpabuf_put_be16(msg, len);
-		wpabuf_put_data(msg, dev->model_name, len);
+		wpabuf_put_u8(msg, ' ');
+		return 0;
 	}
+#endif /* CONFIG_WPS_STRICT */
+	wpabuf_put_be16(msg, len);
+	wpabuf_put_data(msg, dev->model_name, len);
 	return 0;
 }
 
@@ -69,18 +73,20 @@ int wps_build_model_number(struct wps_device_data *dev, struct wpabuf *msg)
 	wpa_printf(MSG_DEBUG, "WPS:  * Model Number");
 	wpabuf_put_be16(msg, ATTR_MODEL_NUMBER);
 	len = dev->model_number ? os_strlen(dev->model_number) : 0;
+#ifndef CONFIG_WPS_STRICT
 	if (len == 0) {
 		/*
 		 * Some deployed WPS implementations fail to parse zero-length
-		 * attributes. As a workaround, send a null character if the
+		 * attributes. As a workaround, send a space character if the
 		 * device attribute string is empty.
 		 */
 		wpabuf_put_be16(msg, 1);
-		wpabuf_put_u8(msg, '\0');
-	} else {
-		wpabuf_put_be16(msg, len);
-		wpabuf_put_data(msg, dev->model_number, len);
+		wpabuf_put_u8(msg, ' ');
+		return 0;
 	}
+#endif /* CONFIG_WPS_STRICT */
+	wpabuf_put_be16(msg, len);
+	wpabuf_put_data(msg, dev->model_number, len);
 	return 0;
 }
 
@@ -92,18 +98,20 @@ static int wps_build_serial_number(struct wps_device_data *dev,
 	wpa_printf(MSG_DEBUG, "WPS:  * Serial Number");
 	wpabuf_put_be16(msg, ATTR_SERIAL_NUMBER);
 	len = dev->serial_number ? os_strlen(dev->serial_number) : 0;
+#ifndef CONFIG_WPS_STRICT
 	if (len == 0) {
 		/*
 		 * Some deployed WPS implementations fail to parse zero-length
-		 * attributes. As a workaround, send a null character if the
+		 * attributes. As a workaround, send a space character if the
 		 * device attribute string is empty.
 		 */
 		wpabuf_put_be16(msg, 1);
-		wpabuf_put_u8(msg, '\0');
-	} else {
-		wpabuf_put_be16(msg, len);
-		wpabuf_put_data(msg, dev->serial_number, len);
+		wpabuf_put_u8(msg, ' ');
+		return 0;
 	}
+#endif /* CONFIG_WPS_STRICT */
+	wpabuf_put_be16(msg, len);
+	wpabuf_put_data(msg, dev->serial_number, len);
 	return 0;
 }
 
@@ -124,18 +132,20 @@ int wps_build_dev_name(struct wps_device_data *dev, struct wpabuf *msg)
 	wpa_printf(MSG_DEBUG, "WPS:  * Device Name");
 	wpabuf_put_be16(msg, ATTR_DEV_NAME);
 	len = dev->device_name ? os_strlen(dev->device_name) : 0;
+#ifndef CONFIG_WPS_STRICT
 	if (len == 0) {
 		/*
 		 * Some deployed WPS implementations fail to parse zero-length
-		 * attributes. As a workaround, send a null character if the
+		 * attributes. As a workaround, send a space character if the
 		 * device attribute string is empty.
 		 */
 		wpabuf_put_be16(msg, 1);
-		wpabuf_put_u8(msg, '\0');
-	} else {
-		wpabuf_put_be16(msg, len);
-		wpabuf_put_data(msg, dev->device_name, len);
+		wpabuf_put_u8(msg, ' ');
+		return 0;
 	}
+#endif /* CONFIG_WPS_STRICT */
+	wpabuf_put_be16(msg, len);
+	wpabuf_put_data(msg, dev->device_name, len);
 	return 0;
 }