diff --git a/configs/olimex-stm32-p407/README.txt b/configs/olimex-stm32-p407/README.txt
index e8efa1f328f..5f99a9b3241 100644
--- a/configs/olimex-stm32-p407/README.txt
+++ b/configs/olimex-stm32-p407/README.txt
@@ -481,5 +481,10 @@ STATUS
   CCM memory is not included in the heap (CONFIG_STM32_CCMEXCLUDE=y) because
   it does not suport DMA, leaving only 128KiB for program usage.
 
-2107-01-23:  Added the knsh configuration and support for the PROTECTED
+2017-01-23:  Added the knsh configuration and support for the PROTECTED
   build mode.
+
+2018-05-29:  Added the zmodem configuration.  Verified correct operation
+  with host-to-target transfers.  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/drivers/serial/serial.c b/drivers/serial/serial.c
index b9d26893693..3b62d1f3420 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -474,7 +474,12 @@ static int uart_tcdrain(FAR uart_dev_t *dev, systime_t timeout)
        * this event, so we have to do a busy wait poll.
        */
 
-      /* Set up for the timeout */
+      /* Set up for the timeout
+       *
+       * REVISIT:  This is a kludge.  The correct fix would be add an
+       * interface to the lower half driver so that the tcflush() operation
+       * all also cause the lower half driver to clear and reset the Tx FIFO.
+       */
 
       start = clock_systimer();