diff --git a/cyassl/ctaocrypt/settings.h b/cyassl/ctaocrypt/settings.h
index c08e6d0c7..d070aaa5c 100644
--- a/cyassl/ctaocrypt/settings.h
+++ b/cyassl/ctaocrypt/settings.h
@@ -133,11 +133,21 @@
 
 
 #ifdef FREERTOS
-    #define NO_WRITEV
-    #define NO_SHA512
-    #define NO_DH
-    #define NO_DSA
-    #define NO_HC128
+    #ifndef NO_WRITEV
+        #define NO_WRITEV
+    #endif
+    #ifndef NO_SHA512
+        #define NO_SHA512
+    #endif
+    #ifndef NO_DH
+        #define NO_DH
+    #endif
+    #ifndef NO_DSA
+        #define NO_DSA
+    #endif
+    #ifndef NO_HC128
+        #define NO_HC128
+    #endif
 
     #ifndef SINGLE_THREADED
         #include "FreeRTOS.h"