diff --git a/components/mdns/include/mdns.h b/components/mdns/include/mdns.h
index a5ebb809f6..4370969d70 100644
--- a/components/mdns/include/mdns.h
+++ b/components/mdns/include/mdns.h
@@ -44,8 +44,8 @@ typedef enum {
  *          Used in mdns_service_add()
  */
 typedef struct {
-    char * key;                             /*!< item key name */
-    char * value;                           /*!< item value string */
+    const char * key;                       /*!< item key name */
+    const char * value;                     /*!< item value string */
 } mdns_txt_item_t;
 
 /**
@@ -81,10 +81,9 @@ typedef struct mdns_result_s {
  *
  * @return
  *     - ESP_OK on success
- *     - ESP_ERR_INVALID_ARG when bad tcpip_if is given
- *     - ESP_ERR_INVALID_STATE when the network returned error
+ *     - ESP_ERR_INVALID_STATE when failed to register event handler
  *     - ESP_ERR_NO_MEM on memory error
- *     - ESP_ERR_WIFI_NOT_INIT when WiFi is not initialized by eps_wifi_init
+ *     - ESP_FAIL when failed to start mdns task
  */
 esp_err_t mdns_init();
 
@@ -127,13 +126,14 @@ esp_err_t mdns_instance_name_set(const char * instance_name);
  * @param  service_type     service type (_http, _ftp, etc)
  * @param  proto            service protocol (_tcp, _udp)
  * @param  port             service port
- * @param  num_items        number of items in TXT data
  * @param  txt              string array of TXT data (eg. {{"var","val"},{"other","2"}})
+ * @param  num_items        number of items in TXT data
  *
  * @return
  *     - ESP_OK success
  *     - ESP_ERR_INVALID_ARG Parameter error
  *     - ESP_ERR_NO_MEM memory error
+ *     - ESP_FAIL failed to add serivce
  */
 esp_err_t mdns_service_add(const char * instance_name, const char * service_type, const char * proto, uint16_t port, mdns_txt_item_t txt[], size_t num_items);
 
@@ -147,7 +147,7 @@ esp_err_t mdns_service_add(const char * instance_name, const char * service_type
  *     - ESP_OK success
  *     - ESP_ERR_INVALID_ARG Parameter error
  *     - ESP_ERR_NOT_FOUND Service not found
- *     - ESP_FAIL unknown error
+ *     - ESP_ERR_NO_MEM memory error
  */
 esp_err_t mdns_service_remove(const char * service_type, const char * proto);
 
@@ -177,6 +177,7 @@ esp_err_t mdns_service_instance_name_set(const char * service_type, const char *
  *     - ESP_OK success
  *     - ESP_ERR_INVALID_ARG Parameter error
  *     - ESP_ERR_NOT_FOUND Service not found
+ *     - ESP_ERR_NO_MEM memory error
  */
 esp_err_t mdns_service_port_set(const char * service_type, const char * proto, uint16_t port);
 
@@ -185,8 +186,8 @@ esp_err_t mdns_service_port_set(const char * service_type, const char * proto, u
  *
  * @param  service_type service type (_http, _ftp, etc)
  * @param  proto        service protocol (_tcp, _udp)
- * @param  num_items    number of items in TXT data
  * @param  txt          array of TXT data (eg. {{"var","val"},{"other","2"}})
+ * @param  num_items    number of items in TXT data
  *
  * @return
  *     - ESP_OK success
diff --git a/components/mdns/mdns.c b/components/mdns/mdns.c
index 8c9767942a..e88672f82b 100644
--- a/components/mdns/mdns.c
+++ b/components/mdns/mdns.c
@@ -2886,7 +2886,7 @@ void mdns_parse_packet(mdns_rx_packet_t * packet)
                         col = 1;
                     } else if (!clas) {
                         col = -1;
-                    } else {
+                    } else if (service) { // only detect txt collision if service existed
                         col = _mdns_check_txt_collision(service->service, data_ptr, data_len);
                     }
                     if (col && !_mdns_server->interfaces[packet->tcpip_if].pcbs[packet->ip_protocol].probe_running) {
diff --git a/components/mdns/private_include/mdns_private.h b/components/mdns/private_include/mdns_private.h
index a5b0747aa0..e3becf28ff 100644
--- a/components/mdns/private_include/mdns_private.h
+++ b/components/mdns/private_include/mdns_private.h
@@ -260,7 +260,7 @@ typedef struct mdns_srv_item_s {
 typedef struct mdns_out_question_s {
     struct mdns_out_question_s * next;
     uint16_t type;
-    uint8_t unicast;
+    bool unicast;
     const char * host;
     const char * service;
     const char * proto;