diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index c60c5f7..99d3065 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -11638,12 +11638,14 @@
                            unsigned char *dstbuf, size_t dlen );
 static tls_prf_fn ssl_tls12prf_from_cs( int ciphersuite_id )
 {
+#if defined(MBEDTLS_SHA512_C)
     const mbedtls_ssl_ciphersuite_t * const ciphersuite_info =
          mbedtls_ssl_ciphersuite_from_id( ciphersuite_id );
 
-#if defined(MBEDTLS_SHA512_C)
     if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
         return( tls_prf_sha384 );
+#else
+    (void) ciphersuite_id;
 #endif
     return( tls_prf_sha256 );
 }