diff --git a/stm-firmware/sd.c b/stm-firmware/sd.c
index c061231..a8f3220 100644
--- a/stm-firmware/sd.c
+++ b/stm-firmware/sd.c
@@ -17,11 +17,12 @@
  * along with the reflow oven controller project.
  * If not, see <http://www.gnu.org/licenses/>.
  */
- 
+
 #include <reflow-controller/sd.h>
 #include "fatfs/ff.h"
 #include "fatfs/shimatta_sdio_driver/shimatta_sdio.h"
 #include <stdint.h>
+#include <string.h>
 #include <helper-macros/helper-macros.h>
 #include <reflow-controller/digio.h>