diff --git a/drivers/wireless/mfrc522.c b/drivers/wireless/mfrc522.c
index 26d02b1286..badc760a33 100644
--- a/drivers/wireless/mfrc522.c
+++ b/drivers/wireless/mfrc522.c
@@ -1611,6 +1611,6 @@ int mfrc522_register(FAR const char *devpath, FAR struct spi_dev_s *spi)
   return ret;
 
 firmware_error:
-  free(dev);
+  kmm_free(dev);
   return -ENODEV;
 }