diff --git a/NEWS b/NEWS
index 09b0635..f43a899 100644
--- a/NEWS
+++ b/NEWS
@@ -16,7 +16,7 @@ API Changes:
       take a constant size for Rx buffer
     - New nfc_initiator_target_is_present() to test is the previously selected
       target is available in the field
-    - nfc_initiator_transceive_bytes() returns NFC_ETGRELEASED when AUTH
+    - nfc_initiator_transceive_bytes() returns NFC_EMFCAUTHFAIL when AUTH
       command failed on a Mifare Classic
     - New nfc_initiator_init_secure_element() to initiate a connection with
       secure element (Only supported with a PN532 with SAM equipped)
diff --git a/include/nfc/nfc.h b/include/nfc/nfc.h
index fe78f84..a5f40a6 100644
--- a/include/nfc/nfc.h
+++ b/include/nfc/nfc.h
@@ -181,6 +181,11 @@ extern  "C" {
    * Error while RF transmission
    */
 #define NFC_ERFTRANS			-20
+  /** @ingroup error
+   * @hideinitializer
+   * MIFARE Classic: authentication failed
+   */
+#define NFC_EMFCAUTHFAIL		-30
   /** @ingroup error
    * @hideinitializer
    * Software error (allocation, file/pipe creation, etc.)
diff --git a/libnfc/chips/pn53x.c b/libnfc/chips/pn53x.c
index 717824d..3b89252 100644
--- a/libnfc/chips/pn53x.c
+++ b/libnfc/chips/pn53x.c
@@ -285,15 +285,12 @@ pn53x_transceive(struct nfc_device *pnd, const uint8_t *pbtTx, const size_t szTx
       break;
     case EMFAUTH:
       // When a MIFARE Classic AUTH fails, the tag is automatically in HALT state
-      res = NFC_ETGRELEASED;
+      res = NFC_EMFCAUTHFAIL;
       break;
     default:
       res = NFC_ECHIP;
       break;
   };
-  /*
-    { EMFAUTH, "Mifare Authentication Error" },
-  */
 
   if (res < 0) {
     pnd->last_error = res;
diff --git a/libnfc/nfc.c b/libnfc/nfc.c
index 2e25ddb..55454a9 100644
--- a/libnfc/nfc.c
+++ b/libnfc/nfc.c
@@ -632,7 +632,7 @@ nfc_initiator_deselect_target(nfc_device *pnd)
  *
  * @warning The configuration option \a NP_HANDLE_PARITY must be set to \c true (the default value).
  *
- * @note When used with MIFARE Classic, NFC_ETGRELEASED error is returned if authentication command failed. You need to re-select the tag to operate with.
+ * @note When used with MIFARE Classic, NFC_EMFCAUTHFAIL error is returned if authentication command failed. You need to re-select the tag to operate with.
  *
  */
 int