diff --git a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c
index 0264b58..0e5e09d 100644
--- a/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c
+++ b/vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c
@@ -159,16 +159,24 @@ static int json_extract_frame(uint8_t *buf, uint16_t *len, char *frame_out, uint
 
 /* 4.1 pwd_verify */
 static void handle_pwd_verify(uint8_t socket, uint32_t msg_id, const char *json) {
+    PRINT("JSON: pwd_verify handler entered\n");
     char *data = json_get_data_str(json);
     if (!data) {
+        PRINT("JSON: pwd_verify — data is NULL\n");
         json_send_error(socket, msg_id, "pwd_verify", JSON_CODE_PARAM_ERR, "missing data");
         return;
     }
+    PRINT("JSON: pwd_verify — data=[%s]\n", data);
 
     char password[16] = {0};
     json_get_str_field(data, "\"password\"", password, sizeof(password));
     free(data);
 
+    PRINT("JSON: pwd_verify — password=[%s] len=%d\n", password, strlen(password));
+    PRINT("JSON: pwd_verify — dev_pwd=[%c%c%c%c%c%c]\n",
+          g_dev_password[0], g_dev_password[1], g_dev_password[2],
+          g_dev_password[3], g_dev_password[4], g_dev_password[5]);
+
     if (strlen(password) == 0) {
         json_send_error(socket, msg_id, "pwd_verify", JSON_CODE_PARAM_ERR, "missing password");
         return;
@@ -551,7 +559,10 @@ static void json_process_frame(uint8_t socket, const char *frame) {
     char cmd[32] = {0};
     json_get_cmd(frame, cmd, sizeof(cmd));
 
+    PRINT("JSON dispatch: msg_id=%lu cmd=[%s] len=%d\n", msg_id, cmd, strlen(cmd));
+
     if (strlen(cmd) == 0) {
+        PRINT("JSON: empty cmd, sending error\n");
         json_send_error(socket, msg_id, "", JSON_CODE_PARAM_ERR, "missing cmd field");
         return;
     }
@@ -560,12 +571,15 @@ static void json_process_frame(uint8_t socket, const char *frame) {
     int handled = 0;
     for (int i = 0; i < JSON_CMD_COUNT; i++) {
         if (strcmp(cmd, g_cmd_table[i].cmd) == 0) {
+            PRINT("JSON: matched cmd[%d]=%s, need_auth=%d, auth_state=%d\n",
+                  i, g_cmd_table[i].cmd, g_cmd_table[i].need_auth, g_json_auth_state);
             // Check auth
             if (g_cmd_table[i].need_auth && g_json_auth_state != JSON_STATE_AUTHED) {
                 json_send_error(socket, msg_id, cmd, JSON_CODE_NOT_AUTHED, "not authenticated");
                 handled = 1;
                 break;
             }
+            PRINT("JSON: calling handler for %s\n", cmd);
             g_cmd_table[i].handler(socket, msg_id, frame);
             handled = 1;
             break;
@@ -574,7 +588,7 @@ static void json_process_frame(uint8_t socket, const char *frame) {
 
     if (!handled) {
         json_send_error(socket, msg_id, cmd, JSON_CODE_UNSUPPORTED, "unsupported command");
-        PRINT("JSON: unsupported cmd: %s\n", cmd);
+        PRINT("JSON: unsupported cmd: [%s]\n", cmd);
     }
 }