diff --git a/cpukit/dev/flash/flashdev.c b/cpukit/dev/flash/flashdev.c
index be85593201..8363ac96b1 100644
--- a/cpukit/dev/flash/flashdev.c
+++ b/cpukit/dev/flash/flashdev.c
@@ -390,6 +390,8 @@ static int rtems_flashdev_ioctl(
     case RTEMS_FLASHDEV_IOCTL_WRITE_BLOCK_SIZE:
       err = rtems_flashdev_ioctl_write_block_size( flash, arg );
       break;
+    default:
+      err = EINVAL;
   }
 
   rtems_flashdev_release( flash );