diff --git a/uisimulator/win32/uisw32.c b/uisimulator/win32/uisw32.c
index 3cfa3aed7c..9a8351c3c5 100644
--- a/uisimulator/win32/uisw32.c
+++ b/uisimulator/win32/uisw32.c
@@ -19,6 +19,8 @@
 
 #include <windows.h>
 #include <process.h>
+#include <stdlib.h>
+#include <fcntl.h>
 #include "uisw32.h"
 #include "resource.h"
 #include "button.h"
@@ -36,6 +38,8 @@ extern void					new_key(int key);
 
 void button_event(int key, bool pressed);
 
+extern int _fmode;
+
 // variables
 HWND                                hGUIWnd; // the GUI window handle
 unsigned int                        uThreadID; // id of mod thread
@@ -308,6 +312,9 @@ int WINAPI WinMain (
     (void)lpCmd;
     (void)nShowCmd;
 
+    /* default file mode should be O_BINARY to be consistent with rockbox */
+    _fmode = _O_BINARY;
+
     if (!GUIStartup ())
         return 0;