From 96d6cb72863a49baf55beb0fcc7f4ff4f828e9b0 Mon Sep 17 00:00:00 2001
From: Kees Bakker <kees@sodaq.com>
Date: Sat, 16 Apr 2016 17:23:10 +0200
Subject: [PATCH] SD: File open with O_WRITE would always append, even when
 O_APPEND is off

Without this fix it is not possible to open an existing file and truncate
the contents.
---
 libraries/SD/src/SD.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/SD/src/SD.cpp b/libraries/SD/src/SD.cpp
index 2afb9d9af1d..f5362c0fd23 100644
--- a/libraries/SD/src/SD.cpp
+++ b/libraries/SD/src/SD.cpp
@@ -465,7 +465,7 @@ File SDClass::open(const char *filepath, uint8_t mode) {
     parentdir.close();
   }
 
-  if (mode & (O_APPEND | O_WRITE)) 
+  if ((mode & (O_APPEND | O_WRITE)) == (O_APPEND | O_WRITE))
     file.seekSet(file.fileSize());
   return File(file, filepath);
 }