diff --git a/knots/timeout.scm b/knots/timeout.scm
index 21c2267..552d079 100644
--- a/knots/timeout.scm
+++ b/knots/timeout.scm
@@ -119,19 +119,17 @@
 
 (define (make-wait-operation ready? schedule-when-ready port
                              port-ready-fd this-procedure)
-  ((module-ref (resolve-interface '(fibers operations))
-               'make-base-operation)
-   #f
-   (lambda _
-     (and (ready? port) values))
-   (lambda (flag sched resume)
-     (define (commit)
-       (match (atomic-box-compare-and-swap! flag 'W 'S)
-         ('W (resume values))
-         ('C (commit))
-         ('S #f)))
-     (schedule-when-ready
-      sched (port-ready-fd port) commit))))
+  (make-base-operation #f
+                       (lambda _
+                         (and (ready? port) values))
+                       (lambda (flag sched resume)
+                         (define (commit)
+                           (match (atomic-box-compare-and-swap! flag 'W 'S)
+                             ('W (resume values))
+                             ('C (commit))
+                             ('S #f)))
+                         (schedule-when-ready
+                          sched (port-ready-fd port) commit))))
 
 (define (wait-until-port-readable-operation port)
   "Make an operation that will succeed when PORT is readable."