From 9ac16049b86e56cb757d92145c21fb648f3f850d Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Sun, 27 May 2018 08:43:22 -0600
Subject: [PATCH] apps/system/zmodem:  Fix an incompatibility with the way that
 CRCs are calculated.

---
 system/zmodem/README.txt | 3 ++-
 system/zmodem/zm_proto.c | 5 +----
 system/zmodem/zm_send.c  | 1 -
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/system/zmodem/README.txt b/system/zmodem/README.txt
index 47d573c15..15fd638e2 100755
--- a/system/zmodem/README.txt
+++ b/system/zmodem/README.txt
@@ -80,9 +80,10 @@ Using NuttX Zmodem with a Linux Host
 
       $ sudo stty -F /dev/ttyS0 9600     # Select 9600 BAUD
       $ sudo stty -F /dev/ttyS0 crtscts  # Enables CTS/RTS handshaking *
+      $ sudo stty -F /dev/ttyS0 raw      # Puts the TTY in raw mode
       $ sudo stty -F /dev/ttyS0          # Show the TTY configuration
 
-      * Only is hardware flow control is enabled.
+      * Only if hardware flow control is enabled.
 
     Start rz on the Linux host (using /dev/ttyS0 as an example):
 
diff --git a/system/zmodem/zm_proto.c b/system/zmodem/zm_proto.c
index 05edc46f6..083af29b9 100644
--- a/system/zmodem/zm_proto.c
+++ b/system/zmodem/zm_proto.c
@@ -235,11 +235,10 @@ int zm_senddata(FAR struct zm_state_s *pzm, FAR const uint8_t *buffer,
 
   *ptr++ = term;
 
-  /* Calcualate and transfer the final CRC value */
+  /* Calculate and transfer the final CRC value */
 
   if (zbin == ZBIN)
     {
-      crc = (uint32_t)crc16part(g_zeroes, 2, (uint16_t)crc);
       ptr = zm_putzdle(pzm, ptr, (crc >> 8) & 0xff);
       ptr = zm_putzdle(pzm, ptr, crc & 0xff);
     }
@@ -314,7 +313,6 @@ int zm_sendhexhdr(FAR struct zm_state_s *pzm, int type,
 
   /* crc-1 crc-2 */
 
-  crc = crc16part(g_zeroes, 2, crc);
   ptr = zm_puthex8(ptr, (crc >> 8) & 0xff);
   ptr = zm_puthex8(ptr, crc & 0xff);
 
@@ -391,7 +389,6 @@ int zm_sendbin16hdr(FAR struct zm_state_s *pzm, int type,
 
   /* crc-1 crc-2 */
 
-  crc = crc16part(g_zeroes, 2, crc);
   ptr = zm_putzdle(pzm, ptr, (crc >> 8) & 0xff);
   ptr = zm_putzdle(pzm, ptr, crc & 0xff);
 
diff --git a/system/zmodem/zm_send.c b/system/zmodem/zm_send.c
index 9daeb2789..e872daaaf 100644
--- a/system/zmodem/zm_send.c
+++ b/system/zmodem/zm_send.c
@@ -1047,7 +1047,6 @@ static int zms_sendpacket(FAR struct zm_state_s *pzm)
 
       if (!bcrc32)
         {
-          crc = (uint32_t)crc16part(g_zeroes, 2, (uint16_t)crc);
           ptr = zm_putzdle(pzm, ptr, (crc >> 8) & 0xff);
           ptr = zm_putzdle(pzm, ptr, crc & 0xff);
         }