diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index f3dbba8..77904e0 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -2255,13 +2255,13 @@
              * Handshake headers: type(1) len(3) seq(2) f_off(3) f_len(3) */
             memcpy( ssl->out_msg, cur->p, 6 );
 
-            ssl->out_msg[6] = BYTE_2( frag_off );
-            ssl->out_msg[7] = BYTE_1( frag_off );
-            ssl->out_msg[8] = BYTE_0( frag_off );
+            ssl->out_msg[6] = MBEDTLS_BYTE_2( frag_off );
+            ssl->out_msg[7] = MBEDTLS_BYTE_1( frag_off );
+            ssl->out_msg[8] = MBEDTLS_BYTE_0( frag_off );
 
-            ssl->out_msg[ 9] = BYTE_2( cur_hs_frag_len );
-            ssl->out_msg[10] = BYTE_1( cur_hs_frag_len );
-            ssl->out_msg[11] = BYTE_0( cur_hs_frag_len );
+            ssl->out_msg[ 9] = MBEDTLS_BYTE_2( cur_hs_frag_len );
+            ssl->out_msg[10] = MBEDTLS_BYTE_1( cur_hs_frag_len );
+            ssl->out_msg[11] = MBEDTLS_BYTE_0( cur_hs_frag_len );
 
             MBEDTLS_SSL_DEBUG_BUF( 3, "handshake header", ssl->out_msg, 12 );