diff --git a/platform/sky/platform-conf.h b/platform/sky/platform-conf.h
index 62b92ec97..8ab7fdc23 100644
--- a/platform/sky/platform-conf.h
+++ b/platform/sky/platform-conf.h
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: platform-conf.h,v 1.1 2010/06/23 10:18:05 joxe Exp $
+ * $Id: platform-conf.h,v 1.2 2010/12/16 22:52:27 adamdunkels Exp $
  */
 
 /**
@@ -81,8 +81,12 @@ typedef unsigned long off_t;
 #define LEDS_CONF_YELLOW 0x40
 
 /* DCO speed resynchronization for more robust UART, etc. */
+#ifndef DCOSYNCH_CONF_ENABLED
 #define DCOSYNCH_CONF_ENABLED 1
+#endif /* DCOSYNCH_CONF_ENABLED */
+#ifndef DCOSYNCH_CONF_PERIOD
 #define DCOSYNCH_CONF_PERIOD 30
+#endif /* DCOSYNCH_CONF_PERIOD */
 
 #define ROM_ERASE_UNIT_SIZE  512
 #define XMEM_ERASE_UNIT_SIZE (64*1024L)