-       } else {        \r
-               int res = MifareChkBlockKeys(datain, keyCount, blockNo, keyType, OLD_MF_DBGLEVEL);\r
-               \r
+       } else if (fixed_nonce) {\r
+               res = MifareChkBlockKeysFixedNonce(datain, keyCount, blockNo, keyType, &auth_timeout, OLD_MF_DBGLEVEL);\r
+               if (res > 0) {\r
+                       cmd_send(CMD_ACK, 1, res, 0, NULL, 0); // key found\r
+               } else {\r
+                       cmd_send(CMD_ACK, 0, res, 0, NULL, 0); // no key found or aborted\r
+               }\r
+       } else {\r
+               res = MifareChkBlockKeys(datain, keyCount, blockNo, keyType, &auth_timeout, OLD_MF_DBGLEVEL);\r