diff --git a/include/mbedtls/md.h b/include/mbedtls/md.h
index bf29524..8bcf766 100644
--- a/include/mbedtls/md.h
+++ b/include/mbedtls/md.h
@@ -39,6 +39,8 @@
 #define MBEDTLS_ERR_MD_BAD_INPUT_DATA                     -0x5100  /**< Bad input parameters to function. */
 #define MBEDTLS_ERR_MD_ALLOC_FAILED                       -0x5180  /**< Failed to allocate memory. */
 #define MBEDTLS_ERR_MD_FILE_IO_ERROR                      -0x5200  /**< Opening or reading of file failed. */
+
+/* MBEDTLS_ERR_MD_HW_ACCEL_FAILED is deprecated and should not be used. */
 #define MBEDTLS_ERR_MD_HW_ACCEL_FAILED                    -0x5280  /**< MD hardware accelerator failed. */
 
 #ifdef __cplusplus