diff --git a/include/polarssl/des.h b/include/polarssl/des.h
index 74d5acb..d29bd1d 100644
--- a/include/polarssl/des.h
+++ b/include/polarssl/des.h
@@ -31,7 +31,7 @@
 
 #include <string.h>
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(EFIX64) && !defined(EFI32)
 #include <basetsd.h>
 typedef UINT32 uint32_t;
 #else