diff --git a/include/mbedtls/sha256.h b/include/mbedtls/sha256.h
index 9c52f78..e9cc0ca 100644
--- a/include/mbedtls/sha256.h
+++ b/include/mbedtls/sha256.h
@@ -32,6 +32,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#define MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED                -0x0037  /**< SHA-256 hardware accelerator failed */
+
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
     !defined(inline) && !defined(__cplusplus)
 #define inline __inline