diff --git a/sys/posix/fd.c b/sys/posix/fd.c
index 6029826c7d..d6dd782731 100644
--- a/sys/posix/fd.c
+++ b/sys/posix/fd.c
@@ -17,7 +17,7 @@
 
 #include "fd.h"
 
-#if BOARD == MSB-430
+#ifdef CPU_MSP430
 #define FD_MAX 5
 #else
 #define FD_MAX 15