diff --git a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c
index 420082b..0264b58 100644
--- a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c
+++ b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c
@@ -85,10 +85,7 @@ static uint32_t json_get_msg_id(const char *json) {
 }
 
 static void json_get_cmd(const char *json, char *out, int out_len) {
-    reset_tmp();
-    simple_parse_json(json, "\"cmd\"", g_tmp_value);
-    strncpy(out, g_tmp_value, out_len - 1);
-    out[out_len - 1] = '\0';
+    json_get_str_field(json, "\"cmd\"", out, out_len);
 }
 
 static char *json_get_data_str(const char *json) {