diff --git a/features/filesystem/FileSystem.cpp b/features/filesystem/FileSystem.cpp
index 6429b51f51..0f9eb40e08 100644
--- a/features/filesystem/FileSystem.cpp
+++ b/features/filesystem/FileSystem.cpp
@@ -1,4 +1,3 @@
-
 /* mbed Microcontroller Library
  * Copyright (c) 2006-2013 ARM Limited
  *
@@ -25,6 +24,26 @@ FileSystem::FileSystem(const char *name)
 {
 }
 
+int FileSystem::remove(const char *path)
+{
+    return -ENOSYS;
+}
+
+int FileSystem::rename(const char *path, const char *newpath)
+{
+    return -ENOSYS;
+}
+
+int FileSystem::stat(const char *path, struct stat *st)
+{
+    return -ENOSYS;
+}
+
+int FileSystem::mkdir(const char *path, mode_t mode)
+{
+    return -ENOSYS;
+}
+
 int FileSystem::file_sync(fs_file_t file)
 {
     return 0;
@@ -53,11 +72,6 @@ off_t FileSystem::file_size(fs_file_t file)
     return size;
 }
 
-int FileSystem::mkdir(const char *path, mode_t mode)
-{
-    return -ENOSYS;
-}
-
 int FileSystem::dir_open(fs_dir_t *dir, const char *path)
 {
     return -ENOSYS;
diff --git a/features/filesystem/FileSystem.h b/features/filesystem/FileSystem.h
index 9c851feb29..31477b1741 100644
--- a/features/filesystem/FileSystem.h
+++ b/features/filesystem/FileSystem.h
@@ -71,7 +71,7 @@ public:
      *  @param path     The name of the file to remove.
      *  @return         0 on success, negative error code on failure
      */
-    virtual int remove(const char *path) = 0;
+    virtual int remove(const char *path);
 
     /** Rename a file in the filesystem.
      *
@@ -79,7 +79,7 @@ public:
      *  @param newpath  The name to rename it to
      *  @return         0 on success, negative error code on failure
      */
-    virtual int rename(const char *path, const char *newpath) = 0;
+    virtual int rename(const char *path, const char *newpath);
 
     /** Store information about the file in a stat structure
      *
@@ -87,7 +87,7 @@ public:
      *  @param st       The stat buffer to write to
      *  @return         0 on success, negative error code on failure
      */
-    virtual int stat(const char *path, struct stat *st) = 0;
+    virtual int stat(const char *path, struct stat *st);
 
     /** Create a directory in the filesystem.
      *