diff --git a/programs/pkey/key_app_writer.c b/programs/pkey/key_app_writer.c
index 6a4d0e4..0d531ea 100644
--- a/programs/pkey/key_app_writer.c
+++ b/programs/pkey/key_app_writer.c
@@ -197,7 +197,9 @@
 {
     int ret = 1;
     int exit_code = MBEDTLS_EXIT_FAILURE;
-    char buf[1024];
+#if defined(MBEDTLS_ERROR_C)
+    char buf[200];
+#endif
     int i;
     char *p, *q;
 
@@ -208,7 +210,9 @@
      * Set to sane values
      */
     mbedtls_pk_init( &key );
+#if defined(MBEDTLS_ERROR_C)
     memset( buf, 0, sizeof( buf ) );
+#endif
 
     mbedtls_mpi_init( &N ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q );
     mbedtls_mpi_init( &D ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &DP );
@@ -296,8 +300,7 @@
 
         if( ret != 0 )
         {
-            mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
-            mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile returned -0x%04x - %s\n\n", (unsigned int) -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile returned -0x%04x", (unsigned int) -ret );
             goto exit;
         }
 
@@ -357,8 +360,7 @@
 
         if( ret != 0 )
         {
-            mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
-            mbedtls_printf( " failed\n  !  mbedtls_pk_parse_public_key returned -0x%04x - %s\n\n", (unsigned int) -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_pk_parse_public_key returned -0x%04x", (unsigned int) -ret );
             goto exit;
         }