diff --git a/repl/src/prebake.mjs b/repl/src/prebake.mjs
index a6f33909..ef617621 100644
--- a/repl/src/prebake.mjs
+++ b/repl/src/prebake.mjs
@@ -1,7 +1,7 @@
 import { Pattern, toMidi } from '@strudel.cycles/core';
 import { samples } from '@strudel.cycles/webaudio';
 
-export function prebake() {
+export function prebake(isMock = false) {
   samples(
     {
       piano: {
@@ -41,9 +41,11 @@ export function prebake() {
     // License: CC-by http://creativecommons.org/licenses/by/3.0/ Author: Alexander Holm
     './piano/',
   );
-  fetch('EmuSP12.json')
-    .then(res => res.json())
-    .then(json => samples(json, './EmuSP12/'));
+  if (!isMock) {
+    fetch('EmuSP12.json')
+      .then((res) => res.json())
+      .then((json) => samples(json, './EmuSP12/'));
+  }
 }
 
 const maxPan = toMidi('C8');
diff --git a/repl/src/runtime.mjs b/repl/src/runtime.mjs
index b883cfc6..1802a7ad 100644
--- a/repl/src/runtime.mjs
+++ b/repl/src/runtime.mjs
@@ -123,7 +123,7 @@ const uiHelpersMocked = {
   backgroundImage: id,
 };
 
-prebake();
+prebake(true);
 
 // TODO: refactor to evalScope
 extend(