diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index cc19f47..e4966f0 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -971,7 +971,13 @@
                              unsigned update_hs_digest );
 int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want );
 
-int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_write_handshake_msg_ext( mbedtls_ssl_context *ssl,
+                                         int update_checksum );
+static inline int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl )
+{
+    return( mbedtls_ssl_write_handshake_msg_ext( ssl, 1 /* update checksum */ ) );
+}
+
 int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush );
 int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl );
 
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 76cc2b1..fe26eaa 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -2360,7 +2360,8 @@
  *      (including handshake headers but excluding record headers)
  *   - ssl->out_msg: the record contents (handshake headers + content)
  */
-int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl )
+int mbedtls_ssl_write_handshake_msg_ext( mbedtls_ssl_context *ssl,
+                                         int update_checksum )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const size_t hs_len = ssl->out_msglen - 4;
@@ -2469,7 +2470,7 @@
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
         /* Update running hashes of handshake messages seen */
-        if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST )
+        if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST && update_checksum != 0 )
             ssl->handshake->update_checksum( ssl, ssl->out_msg, ssl->out_msglen );
     }