diff --git a/test/external/process_replay/process_replay.py b/test/external/process_replay/process_replay.py
index fac2407abb..8105017a84 100755
--- a/test/external/process_replay/process_replay.py
+++ b/test/external/process_replay/process_replay.py
@@ -35,7 +35,7 @@ class ProcessReplayWarning(Warning): pass
 
 def recreate_sched(big_sink:UOp) -> list[UOp]:
   becomes_map = get_becomes_map(big_sink)
-  sched_sink = UOp.sink(*[becomes_map.get(x,x) for x in big_sink.src])
+  sched_sink = big_sink.substitute(becomes_map)
   return dedup(u.arg.ast for u in sched_sink.toposort if u.op is Ops.KERNEL)
 
 def recreate_kernel(ast:UOp, opts:Renderer, applied_opts:list[Opt], name:str, _) -> str: