diff --git a/dev/cc2520/cc2520.c b/dev/cc2520/cc2520.c
index b6c0e43fa..b31302c43 100644
--- a/dev/cc2520/cc2520.c
+++ b/dev/cc2520/cc2520.c
@@ -217,6 +217,7 @@ flushrx(void)
   uint8_t dummy;
 
   CC2520_READ_FIFO_BYTE(dummy);
+  (void)dummy;
   CC2520_STROBE(CC2520_INS_SFLUSHRX);
   CC2520_STROBE(CC2520_INS_SFLUSHRX);
 }