diff --git a/src/core/tcp.c b/src/core/tcp.c
index a28b2890..5779fff4 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -1075,7 +1075,8 @@ tcp_poll(struct tcp_pcb *pcb,
 }
 
 /**
- * Purges a TCP PCB. Removes any buffered data and frees the buffer memory.
+ * Purges a TCP PCB. Removes any buffered data and frees the buffer memory
+ * (pcb->ooseq, pcb->unsent and pcb->unacked are freed).
  *
  * @param pcb tcp_pcb to purge. The pcb itself is not deallocated!
  */
diff --git a/src/core/tcp_in.c b/src/core/tcp_in.c
index 8e212cc4..fa061f21 100644
--- a/src/core/tcp_in.c
+++ b/src/core/tcp_in.c
@@ -1235,6 +1235,7 @@ tcp_receive(struct tcp_pcb *pcb)
  * from uIP with only small changes.)
  *
  * Called from tcp_listen_input() and tcp_process().
+ * Currently, only the MSS option is supported!
  *
  * @param pcb the tcp_pcb for which a segment arrived
  */