From 8680f1ab52c3558149f72eacc4caf2f853069eb8 Mon Sep 17 00:00:00 2001
From: Michael du Breuil <wicked.shell.scripts@gmail.com>
Date: Wed, 20 Jun 2018 02:01:08 -0700
Subject: [PATCH] AP_HAL_SITL: Clear UART buffers when opening a port

---
 libraries/AP_HAL_SITL/UARTDriver.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libraries/AP_HAL_SITL/UARTDriver.cpp b/libraries/AP_HAL_SITL/UARTDriver.cpp
index 607fde7d48..f605bc2c37 100644
--- a/libraries/AP_HAL_SITL/UARTDriver.cpp
+++ b/libraries/AP_HAL_SITL/UARTDriver.cpp
@@ -105,6 +105,11 @@ void UARTDriver::begin(uint32_t baud, uint16_t rxSpace, uint16_t txSpace)
         free(s);
     }
 
+    if (hal.console != this) { // don't clear USB buffers (allows early startup messages to escape)
+        _readbuffer.clear();
+        _writebuffer.clear();
+    }
+
     _set_nonblocking(_fd);
 }