diff --git a/system/zmodem/README.txt b/system/zmodem/README.txt
index 25e0f4a68..b399be996 100755
--- a/system/zmodem/README.txt
+++ b/system/zmodem/README.txt
@@ -233,3 +233,10 @@ Status
       serial speeds and with much smaller buffers (although that has not
       been verified as of this writing).
 
+    2018-5-28:
+      Updates to checksum calculations.  Verified correct operation with
+      hardware flow control using the olimex-stm32-p407/zmodem
+      configuration.  Only the host-to-target transfer was verified.
+
+      There appears to be problems still host target-to-host transfers
+      and with use of the NuttX versions of rx/sz on the host.
diff --git a/system/zmodem/zm.h b/system/zmodem/zm.h
index 76bacbe38..0c309c79e 100644
--- a/system/zmodem/zm.h
+++ b/system/zmodem/zm.h
@@ -581,7 +581,10 @@ uint32_t zm_filecrc(FAR struct zm_state_s *pzm, FAR const char *filename);
  * Name: zm_flowc
  *
  * Description:
- *   Enable hardware Rx/Tx flow control
+ *   Enable hardware Rx/Tx flow control.
+ *
+ *   REVISIT:  Consider returning the original termios settings so that they
+ *   could be restored with rx/sz exits.
  *
  ****************************************************************************/
 
diff --git a/system/zmodem/zm_utils.c b/system/zmodem/zm_utils.c
index c0a3ee2ea..c466a05d8 100644
--- a/system/zmodem/zm_utils.c
+++ b/system/zmodem/zm_utils.c
@@ -477,7 +477,10 @@ uint32_t zm_filecrc(FAR struct zm_state_s *pzm, FAR const char *filename)
  * Name: zm_flowc
  *
  * Description:
- *   Enable hardware Rx/Tx flow control
+ *   Enable hardware Rx/Tx flow control.
+ *
+ *   REVISIT:  Consider returning the original termios settings so that they
+ *   could be restored with rx/sz exits.
  *
  ****************************************************************************/