- * The latter is only used in an initial ClientHello for old
- * clients. We check s->read_hash and s->enc_read_ctx to ensure this
- * does not apply during renegotiation
+ * The latter can only be used in the first record of an initial
+ * ClientHello for old clients. Initial ClientHello means
+ * s->first_packet is set and s->server is true. The first record
+ * means s->rlayer.is_first_record is true. Probably this is
+ * sufficient in itself instead of s->first_packet, but I am
+ * cautious. We check s->read_hash and s->enc_read_ctx to ensure
+ * this does not apply during renegotiation.