diff --git a/src/codegen/compile.ml b/src/codegen/compile.ml
index b6aace36dca..7a7dace7661 100644
--- a/src/codegen/compile.ml
+++ b/src/codegen/compile.ml
@@ -6361,9 +6361,11 @@ module FuncDec = struct
       get_cb_index
 
   let ignoring_callback env =
-    let name = "@ignore_callback" in
-    Func.define_built_in env name ["env", I32Type] [] (fun env -> G.nop);
-    compile_unboxed_const (E.add_fun_ptr env (E.built_in env name))
+    (* for one-way calls, we use an invalid table entry as the callback. this
+       way, the callback, when it comes back, will (safely) trap, even if the
+       module has completely changed in between. This way, one-way calls do not
+       get in the way of safe instantaneous upgrades *)
+    compile_unboxed_const (-1l)
 
   let cleanup_callback env =
     let name = "@cleanup_callback" in
diff --git a/test/run-drun/ok/oneshot-callbacks.ic-ref-run.ok b/test/run-drun/ok/oneshot-callbacks.ic-ref-run.ok
index facceb4fe9b..e78b94dda59 100644
--- a/test/run-drun/ok/oneshot-callbacks.ic-ref-run.ok
+++ b/test/run-drun/ok/oneshot-callbacks.ic-ref-run.ok
@@ -53,7 +53,7 @@ debug.print: ping! 1
 debug.print: go 1: 1
 debug.print: ping-async! 1
 debug.print: go 2: 1
-← rejected (RC_CANISTER_ERROR): canister did not respond
+← rejected (RC_CANISTER_ERROR): canister trapped: EvalTrapError :0.1 "uninitialized element -1"
 → update go(false)
 debug.print: go 0: 0
 debug.print: ping! 1
@@ -67,4 +67,4 @@ debug.print: ping! 1
 debug.print: go 1: 1
 debug.print: ping-async! 1
 debug.print: go 2: 1
-← rejected (RC_CANISTER_ERROR): canister did not respond
+← rejected (RC_CANISTER_ERROR): canister trapped: EvalTrapError :0.1 "uninitialized element -1"