diff --git a/programs/pkey/key_app_writer.c b/programs/pkey/key_app_writer.c
index 8a09af5..ed6addf 100644
--- a/programs/pkey/key_app_writer.c
+++ b/programs/pkey/key_app_writer.c
@@ -202,7 +202,9 @@
 {
     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;
 
@@ -220,7 +222,9 @@
     mbedtls_ctr_drbg_init( &ctr_drbg );
 
     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 );
@@ -316,8 +320,7 @@
                                         mbedtls_ctr_drbg_random, &ctr_drbg );
         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;
         }
 
@@ -377,8 +380,7 @@
 
         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;
         }
 
diff --git a/programs/x509/load_roots.c b/programs/x509/load_roots.c
index 8570a0e..e07bed7 100644
--- a/programs/x509/load_roots.c
+++ b/programs/x509/load_roots.c
@@ -105,7 +105,6 @@
     mbedtls_x509_crt cas;
     int ret = 0;
     const char *const *cur;
-    char error_message[200];
 
     mbedtls_x509_crt_init( &cas );
 
@@ -114,9 +113,15 @@
         ret = mbedtls_x509_crt_parse_file( &cas, *cur );
         if( ret != 0 )
         {
+#if defined(MBEDTLS_ERROR_C) || defined(MBEDTLS_ERROR_STRERROR_DUMMY)
+            char error_message[200];
             mbedtls_strerror( ret, error_message, sizeof( error_message ) );
             printf( "\n%s: -0x%04x (%s)\n",
                     *cur, (unsigned) -ret, error_message );
+#else
+            printf( "\n%s: -0x%04x\n",
+                    *cur, (unsigned) -ret );
+#endif
             goto exit;
         }
     }