diff --git a/packages/SwingSet/src/controller/controller.js b/packages/SwingSet/src/controller/controller.js
index d65f2c04ab4..b5f7ca9fd89 100644
--- a/packages/SwingSet/src/controller/controller.js
+++ b/packages/SwingSet/src/controller/controller.js
@@ -26,6 +26,7 @@ import { makeGcAndFinalize } from '../lib-nodejs/gc-and-finalize.js';
 import { insistStorageAPI } from '../lib/storageAPI.js';
 import { provideHostStorage } from './hostStorage.js';
 import {
+  buildKernelBundle,
   swingsetIsInitialized,
   initializeSwingset,
 } from './initializeSwingset.js';
@@ -168,7 +169,8 @@ export function makeStartXSnap(bundles, { snapStore, env, spawn }) {
  *   warehousePolicy?: { maxVatsOnline?: number },
  *   overrideVatManagerOptions?: unknown,
  *   spawn?: typeof import('child_process').spawn,
- *   env?: Record<string, string | undefined>
+ *   env?: Record<string, string | undefined>,
+ *   kernelBundle?: Bundle
  * }} runtimeOptions
  */
 export async function makeSwingsetController(
@@ -238,6 +240,10 @@ export async function makeSwingsetController(
   // see https://github.com/Agoric/SES-shim/issues/292 for details
   harden(console);
 
+  writeSlogObject({ type: 'bundle-kernel-start' });
+  const { kernelBundle = await buildKernelBundle() } = runtimeOptions;
+  writeSlogObject({ type: 'bundle-kernel-finish' });
+
   // FIXME: Put this somewhere better.
   const handlers = process.listeners('unhandledRejection');
   let haveUnhandledRejectionHandler = false;
@@ -254,8 +260,6 @@ export async function makeSwingsetController(
   function kernelRequire(what) {
     assert.fail(X`kernelRequire unprepared to satisfy require(${what})`);
   }
-  // @ts-expect-error assume kernelBundle is set
-  const kernelBundle = JSON.parse(kvStore.get('kernelBundle'));
   writeSlogObject({ type: 'import-kernel-start' });
   const kernelNS = await importBundle(kernelBundle, {
     filePrefix: 'kernel/...',
@@ -515,7 +519,7 @@ export async function makeSwingsetController(
  * @param {SwingSetConfig} config
  * @param {string[]} argv
  * @param {{ hostStorage?: HostStore, env?: Record<string, string>, verbose?:
- *   boolean, kernelBundles?: Record<string, string>, debugPrefix?: string,
+ *   boolean, kernelBundles?: Record<string, Bundle>, debugPrefix?: string,
  *   slogCallbacks?: unknown, testTrackDecref?: unknown, warehousePolicy?: {
  *   maxVatsOnline?: number }, slogFile?: string }} runtimeOptions
  * @typedef { import('@agoric/swing-store').KVStore } KVStore
@@ -529,12 +533,15 @@ export async function buildVatController(
     hostStorage = provideHostStorage(),
     env,
     verbose,
-    kernelBundles,
+    kernelBundles: kernelAndOtherBundles = {},
     debugPrefix,
     slogCallbacks,
     warehousePolicy,
     slogFile,
   } = runtimeOptions;
+  const { kernel: kernelBundle, ...otherBundles } = kernelAndOtherBundles;
+  const kernelBundles = runtimeOptions.kernelBundles ? otherBundles : undefined;
+
   const actualRuntimeOptions = {
     env,
     verbose,
@@ -542,6 +549,7 @@ export async function buildVatController(
     slogCallbacks,
     warehousePolicy,
     slogFile,
+    kernelBundle,
   };
   const initializationOptions = { verbose, kernelBundles };
   let bootstrapResult;
diff --git a/packages/SwingSet/src/controller/initializeSwingset.js b/packages/SwingSet/src/controller/initializeSwingset.js
index d7c7b491c7f..61aebcc3b93 100644
--- a/packages/SwingSet/src/controller/initializeSwingset.js
+++ b/packages/SwingSet/src/controller/initializeSwingset.js
@@ -28,38 +28,38 @@ const { keys, values, fromEntries } = Object;
 const allValues = async obj =>
   fromEntries(zip(keys(obj), await Promise.all(values(obj))));
 
+const bundleRelative = rel =>
+  bundleSource(new URL(rel, import.meta.url).pathname);
+const bundleRelativeGE = rel =>
+  bundleSource(new URL(rel, import.meta.url).pathname, { format: 'getExport' });
+
 /**
- * Build the source bundles for the kernel and xsnap vat worker.
- *
- * @param {object} [options]
- * @param {ModuleFormat} [options.bundleFormat]
+ * Build the source bundles for the kernel. makeSwingsetController()
+ * calls this on each launch, to get the
+ * current kernel sources
  */
-export async function buildKernelBundles(options = {}) {
-  // this takes 2.7s on my computer
-
-  const { bundleFormat = undefined } = options;
-
-  const src = rel =>
-    bundleSource(new URL(rel, import.meta.url).pathname, {
-      format: bundleFormat,
-    });
-  const srcGE = rel =>
-    bundleSource(new URL(rel, import.meta.url).pathname, {
-      format: 'getExport',
-    });
+export async function buildKernelBundle() {
+  // this takes about 1.0s on my computer
+  const kernelBundle = await bundleRelative('../kernel/kernel.js');
+  return harden(kernelBundle);
+}
 
+/**
+ * Build the source bundles for built-in vats and devices, and for the
+ * xsnap vat worker.
+ */
+export async function buildVatAndDeviceBundles() {
   const bundles = await allValues({
-    kernel: src('../kernel/kernel.js'),
-    adminDevice: src('../devices/vat-admin/device-vat-admin.js'),
-    adminVat: src('../vats/vat-admin/vat-vat-admin.js'),
-    comms: src('../vats/comms/index.js'),
-    vattp: src('../vats/vattp/vat-vattp.js'),
-    timer: src('../vats/timer/vat-timer.js'),
-
-    lockdown: srcGE(
+    adminDevice: bundleRelative('../devices/vat-admin/device-vat-admin.js'),
+    adminVat: bundleRelative('../vats/vat-admin/vat-vat-admin.js'),
+    comms: bundleRelative('../vats/comms/index.js'),
+    vattp: bundleRelative('../vats/vattp/vat-vattp.js'),
+    timer: bundleRelative('../vats/timer/vat-timer.js'),
+
+    lockdown: bundleRelativeGE(
       '../supervisors/subprocess-xsnap/lockdown-subprocess-xsnap.js',
     ),
-    supervisor: srcGE(
+    supervisor: bundleRelativeGE(
       '../supervisors/subprocess-xsnap/supervisor-subprocess-xsnap.js',
     ),
   });
@@ -67,6 +67,22 @@ export async function buildKernelBundles(options = {}) {
   return harden(bundles);
 }
 
+// Unit tests can call this to amortize the bundling costs: pass the
+// result to initializeSwingset's initializationOptions.kernelBundles
+// (for the vat/device/worker bundles), and you can pass .kernelBundle
+// individually to makeSwingsetController's
+// runtimeOptions.kernelBundle
+
+// Tests can also pass the whole result to buildVatController's
+// runtimeOptions.kernelBundles, which will pass it through to both.
+
+export async function buildKernelBundles() {
+  const bp = buildVatAndDeviceBundles();
+  const kp = buildKernelBundle();
+  const [vdBundles, kernelBundle] = await Promise.all([bp, kp]);
+  return harden({ kernel: kernelBundle, ...vdBundles });
+}
+
 function byName(a, b) {
   if (a.name < b.name) {
     return -1;
@@ -256,7 +272,7 @@ function sortObjectProperties(obj, firsts = []) {
   return result;
 }
 
-/** @typedef {{ kernelBundles?: Record<string, string>, verbose?: boolean,
+/** @typedef {{ kernelBundles?: Record<string, Bundle>, verbose?: boolean,
  *              addVatAdmin?: boolean, addComms?: boolean, addVattp?: boolean,
  *              addTimer?: boolean,
  *            }} InitializationOptions
@@ -318,9 +334,7 @@ export async function initializeSwingset(
   }
 
   const {
-    kernelBundles = await buildKernelBundles({
-      bundleFormat: config.bundleFormat,
-    }),
+    kernelBundles = await buildVatAndDeviceBundles(),
     verbose,
     addVatAdmin = true,
     addComms = true,
@@ -328,7 +342,6 @@ export async function initializeSwingset(
     addTimer = true,
   } = initializationOptions;
 
-  kvStore.set('kernelBundle', JSON.stringify(kernelBundles.kernel));
   kvStore.set('lockdownBundle', JSON.stringify(kernelBundles.lockdown));
   kvStore.set('supervisorBundle', JSON.stringify(kernelBundles.supervisor));
 
diff --git a/packages/SwingSet/src/kernel/state/kernelKeeper.js b/packages/SwingSet/src/kernel/state/kernelKeeper.js
index 875f0fcdc97..c4a85811eed 100644
--- a/packages/SwingSet/src/kernel/state/kernelKeeper.js
+++ b/packages/SwingSet/src/kernel/state/kernelKeeper.js
@@ -52,7 +52,6 @@ const enableKernelGC = true;
 // device.nextID = $NN
 // meter.nextID = $NN // used to make m$NN
 
-// kernelBundle = JSON(bundle)
 // namedBundleID.$NAME = bundleID
 // bundle.$BUNDLEID = JSON(bundle)
 //
diff --git a/packages/SwingSet/test/device-hooks/test-device-hooks.js b/packages/SwingSet/test/device-hooks/test-device-hooks.js
index 8ce832df808..94b56bd2ba8 100644
--- a/packages/SwingSet/test/device-hooks/test-device-hooks.js
+++ b/packages/SwingSet/test/device-hooks/test-device-hooks.js
@@ -59,8 +59,10 @@ test('add hook', async t => {
     addVattp: false,
     addTimer: false,
   };
+  const { kernelBundle } = t.context.data.kernelBundles;
+  const runtimeOpts = { kernelBundle };
   await initializeSwingset(config, [], hostStorage, initOpts);
-  const c = await makeSwingsetController(hostStorage, {});
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
 
   let hookreturn;
   function setHookReturn(args, slots = []) {
diff --git a/packages/SwingSet/test/device-mailbox/test-device-mailbox.js b/packages/SwingSet/test/device-mailbox/test-device-mailbox.js
index 7eb991419fb..1ce98d2c49c 100644
--- a/packages/SwingSet/test/device-mailbox/test-device-mailbox.js
+++ b/packages/SwingSet/test/device-mailbox/test-device-mailbox.js
@@ -13,6 +13,7 @@ import {
   buildMailboxStateMap,
   buildMailbox,
 } from '../../src/devices/mailbox/mailbox.js';
+import { bundleOpts } from '../util.js';
 
 test.before(async t => {
   const kernelBundles = await buildKernelBundles();
@@ -37,13 +38,14 @@ test('mailbox outbound', async t => {
       },
     },
   };
-  const deviceEndowments = {
+  const devEndows = {
     mailbox: { ...mb.endowments },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, ['mailbox1'], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, ['mailbox1'], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   await c.run();
   // exportToData() provides plain Numbers to the host that needs to convey the messages
   t.deepEqual(s.exportToData(), {
@@ -85,13 +87,14 @@ test('mailbox inbound', async t => {
       },
     },
   };
-  const deviceEndowments = {
+  const devEndows = {
     mailbox: { ...mb.endowments },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, ['mailbox2'], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, ['mailbox2'], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   await c.run();
   const m1 = [1, 'msg1'];
   const m2 = [2, 'msg2'];
@@ -143,23 +146,25 @@ async function initializeMailboxKernel(t) {
       },
     },
   };
+  const { initOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
   await initializeSwingset(
     config,
     ['mailbox-determinism'],
     hostStorage,
-    t.context.data,
+    initOpts,
   );
   return hostStorage;
 }
 
-async function makeMailboxKernel(hostStorage) {
+async function makeMailboxKernel(t, hostStorage) {
   const s = buildMailboxStateMap();
   const mb = buildMailbox(s);
-  const deviceEndowments = {
+  const devEndows = {
     mailbox: { ...mb.endowments },
   };
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  const { runtimeOpts } = bundleOpts(t.context.data);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   c.pinVatRoot('bootstrap');
   await c.run();
   return [c, mb];
@@ -169,8 +174,8 @@ test('mailbox determinism', async t => {
   // we run two kernels in parallel
   const hostStorage1 = await initializeMailboxKernel(t);
   const hostStorage2 = await initializeMailboxKernel(t);
-  const [c1a, mb1a] = await makeMailboxKernel(hostStorage1);
-  const [c2, mb2] = await makeMailboxKernel(hostStorage2);
+  const [c1a, mb1a] = await makeMailboxKernel(t, hostStorage1);
+  const [c2, mb2] = await makeMailboxKernel(t, hostStorage2);
 
   // they get the same inbound message
   const msg1 = [[1, 'msg1']];
@@ -195,7 +200,7 @@ test('mailbox determinism', async t => {
   );
 
   // then one is restarted, but the other keeps running
-  const [c1b, mb1b] = await makeMailboxKernel(hostStorage1);
+  const [c1b, mb1b] = await makeMailboxKernel(t, hostStorage1);
 
   // Now we repeat delivery of that message to both. The mailbox should send
   // it to vattp, even though it's duplicate, because the mailbox doesn't
diff --git a/packages/SwingSet/test/devices/test-devices.js b/packages/SwingSet/test/devices/test-devices.js
index 31c579cffa0..e7277cd1de1 100644
--- a/packages/SwingSet/test/devices/test-devices.js
+++ b/packages/SwingSet/test/devices/test-devices.js
@@ -12,6 +12,7 @@ import {
   buildKernelBundles,
 } from '../../src/index.js';
 import buildCommand from '../../src/devices/command/command.js';
+import { bundleOpts } from '../util.js';
 
 function capdata(body, slots = []) {
   return harden({ body, slots });
@@ -61,9 +62,10 @@ test.serial('d0', async t => {
       },
     },
   };
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage);
-  const c = await makeSwingsetController(hostStorage, {});
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   await c.run();
 
   // console.log(util.inspect(c.dump(), { depth: null }));
@@ -108,15 +110,16 @@ test.serial('d1', async t => {
       },
     },
   };
-  const deviceEndowments = {
+  const devEndows = {
     d1: {
       shared: sharedArray,
     },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   c.pinVatRoot('bootstrap');
   await c.run();
 
@@ -149,9 +152,10 @@ async function test2(t, mode) {
       },
     },
   };
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, {});
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   c.pinVatRoot('bootstrap');
   await c.run(); // startup
 
@@ -238,10 +242,11 @@ test.serial('device state', async t => {
     },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   // The initial state should be missing (null). Then we set it with the call
   // from bootstrap, and read it back.
-  await initializeSwingset(config, ['write+read'], hostStorage, t.context.data);
-  const c1 = await makeSwingsetController(hostStorage, {});
+  await initializeSwingset(config, ['write+read'], hostStorage, initOpts);
+  const c1 = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   const d3 = c1.deviceNameToID('d3');
   await c1.run();
   t.deepEqual(c1.dump().log, ['undefined', 'w+r', 'called', 'got {"s":"new"}']);
@@ -266,13 +271,14 @@ test.serial('command broadcast', async t => {
       },
     },
   };
-  const deviceEndowments = {
+  const devEndows = {
     command: { ...cm.endowments },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   c.pinVatRoot('bootstrap');
   c.queueToVatRoot('bootstrap', 'doCommand1', [], 'panic');
   await c.run();
@@ -294,13 +300,14 @@ test.serial('command deliver', async t => {
       },
     },
   };
-  const deviceEndowments = {
+  const devEndows = {
     command: { ...cm.endowments },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   c.pinVatRoot('bootstrap');
   c.queueToVatRoot('bootstrap', 'doCommand2', [], 'panic');
   await c.run();
@@ -339,9 +346,10 @@ test.serial('liveslots throws when D() gets promise', async t => {
       },
     },
   };
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, {});
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   c.pinVatRoot('bootstrap');
 
   // When liveslots catches an attempt to send a promise into D(), it throws
@@ -377,9 +385,10 @@ test.serial('syscall.callNow(promise) is vat-fatal', async t => {
       },
     },
   };
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, {});
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   c.pinVatRoot('bootstrap');
   await c.run();
 
@@ -413,13 +422,14 @@ test.serial('device errors cause vat-catchable D error', async t => {
     },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const bootstrapResult = await initializeSwingset(
     config,
     [],
     hostStorage,
-    t.context.data,
+    initOpts,
   );
-  const c = await makeSwingsetController(hostStorage, {});
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   await c.run();
 
   t.is(c.kpStatus(bootstrapResult), 'fulfilled'); // not 'rejected'
@@ -451,13 +461,14 @@ test.serial('foreign device nodes cause a catchable error', async t => {
     },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const bootstrapResult = await initializeSwingset(
     config,
     [],
     hostStorage,
-    t.context.data,
+    initOpts,
   );
-  const c = await makeSwingsetController(hostStorage, {});
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   await c.run();
 
   t.is(c.kpStatus(bootstrapResult), 'fulfilled'); // not 'rejected'
diff --git a/packages/SwingSet/test/devices/test-raw-device.js b/packages/SwingSet/test/devices/test-raw-device.js
index 9a4cdad75c8..9d276381c17 100644
--- a/packages/SwingSet/test/devices/test-raw-device.js
+++ b/packages/SwingSet/test/devices/test-raw-device.js
@@ -11,6 +11,7 @@ import {
   makeSwingsetController,
   buildKernelBundles,
 } from '../../src/index.js';
+import { bundleOpts } from '../util.js';
 
 function dfile(name) {
   return new URL(`./${name}`, import.meta.url).pathname;
@@ -41,15 +42,16 @@ test('d1', async t => {
       },
     },
   };
-  const deviceEndowments = {
+  const devEndows = {
     dr: {
       shared: sharedArray,
     },
   };
 
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, t.context.data);
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   c.pinVatRoot('bootstrap');
   await c.run();
 
diff --git a/packages/SwingSet/test/test-message-patterns.js b/packages/SwingSet/test/test-message-patterns.js
index 61257039621..f89cabc1aff 100644
--- a/packages/SwingSet/test/test-message-patterns.js
+++ b/packages/SwingSet/test/test-message-patterns.js
@@ -19,6 +19,7 @@ import {
   buildVatController,
   buildKernelBundles,
 } from '../src/index.js';
+import { bundleOpts } from './util.js';
 import { buildLoopbox } from '../src/devices/loopbox/loopbox.js';
 import { buildPatterns } from './message-patterns.js';
 
@@ -127,7 +128,7 @@ for (const name of Array.from(bp.patterns.keys()).sort()) {
 }
 
 export async function runVatsInComms(t, name) {
-  const { commsConfig, kernelBundles } = t.context.data;
+  const { commsConfig } = t.context.data;
   const { passOneMessage, loopboxSrcPath, loopboxEndowments } =
     buildLoopbox('queued');
   const devices = {
@@ -139,12 +140,13 @@ export async function runVatsInComms(t, name) {
     },
   };
   const config = { ...commsConfig, devices };
-  const deviceEndowments = {
+  const devEndows = {
     loopbox: { ...loopboxEndowments },
   };
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
   const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [name], hostStorage, { kernelBundles });
-  const c = await makeSwingsetController(hostStorage, deviceEndowments);
+  await initializeSwingset(config, [name], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, devEndows, runtimeOpts);
   t.teardown(c.shutdown);
 
   // await runWithTrace(c);
diff --git a/packages/SwingSet/test/upgrade/test-upgrade-replay.js b/packages/SwingSet/test/upgrade/test-upgrade-replay.js
index 775725f629e..2454a5f9000 100644
--- a/packages/SwingSet/test/upgrade/test-upgrade-replay.js
+++ b/packages/SwingSet/test/upgrade/test-upgrade-replay.js
@@ -9,7 +9,7 @@ import {
   initializeSwingset,
   makeSwingsetController,
 } from '../../src/index.js';
-import { capargs } from '../util.js';
+import { capargs, bundleOpts } from '../util.js';
 
 function bfile(name) {
   return new URL(name, import.meta.url).pathname;
@@ -43,13 +43,12 @@ test('replay after upgrade', async t => {
       upton: { sourceSpec: bfile('vat-upton-replay.js') },
     },
   };
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data);
 
   const hostStorage1 = provideHostStorage();
   {
-    await initializeSwingset(copy(config), [], hostStorage1, {
-      kernelBundles: t.context.data.kernelBundles,
-    });
-    const c1 = await makeSwingsetController(hostStorage1);
+    await initializeSwingset(copy(config), [], hostStorage1, initOpts);
+    const c1 = await makeSwingsetController(hostStorage1, {}, runtimeOpts);
     c1.pinVatRoot('bootstrap');
     await c1.run();
 
@@ -70,7 +69,7 @@ test('replay after upgrade', async t => {
   const hostStorage2 = provideHostStorage();
   setAllState(hostStorage2, state1);
   {
-    const c2 = await makeSwingsetController(hostStorage2);
+    const c2 = await makeSwingsetController(hostStorage2, {}, runtimeOpts);
     c2.pinVatRoot('bootstrap');
     await c2.run();
 
diff --git a/packages/SwingSet/test/util.js b/packages/SwingSet/test/util.js
index d98d1cea0ac..6c75f5ccc59 100644
--- a/packages/SwingSet/test/util.js
+++ b/packages/SwingSet/test/util.js
@@ -171,3 +171,10 @@ export function makeKernelEndowments() {
     createSHA256,
   };
 }
+
+export function bundleOpts(data, extraRuntimeOpts) {
+  const { kernel: kernelBundle, ...kernelBundles } = data.kernelBundles;
+  const initOpts = { kernelBundles };
+  const runtimeOpts = { kernelBundle, ...extraRuntimeOpts };
+  return { initOpts, runtimeOpts };
+}
diff --git a/packages/SwingSet/test/vat-admin/test-create-vat.js b/packages/SwingSet/test/vat-admin/test-create-vat.js
index 2b48e53b050..ddbe039e7e7 100644
--- a/packages/SwingSet/test/vat-admin/test-create-vat.js
+++ b/packages/SwingSet/test/vat-admin/test-create-vat.js
@@ -10,7 +10,7 @@ import {
   makeSwingsetController,
   loadBasedir,
 } from '../../src/index.js';
-import { capSlot } from '../util.js';
+import { capSlot, bundleOpts } from '../util.js';
 import { extractMethod } from '../../src/lib/kdebug.js';
 
 function nonBundleFunction(_E) {
@@ -51,7 +51,7 @@ test.before(async t => {
 });
 
 async function doTestSetup(t, enableSlog = false) {
-  const { bundles, kernelBundles } = t.context.data;
+  const { bundles } = t.context.data;
   const config = await loadBasedir(new URL('./', import.meta.url).pathname);
   config.defaultManagerType = 'xs-worker';
   config.bundles = {
@@ -60,8 +60,6 @@ async function doTestSetup(t, enableSlog = false) {
     brokenRoot: { bundle: bundles.brokenRootVatBundle },
     brokenHang: { bundle: bundles.brokenHangVatBundle },
   };
-  const hostStorage = provideHostStorage();
-  await initializeSwingset(config, [], hostStorage, { kernelBundles });
   let doSlog = false;
   function slogSender(_, s) {
     if (!doSlog) return;
@@ -74,7 +72,10 @@ async function doTestSetup(t, enableSlog = false) {
       console.log(JSON.stringify(o));
     }
   }
-  const c = await makeSwingsetController(hostStorage, {}, { slogSender });
+  const { initOpts, runtimeOpts } = bundleOpts(t.context.data, { slogSender });
+  const hostStorage = provideHostStorage();
+  await initializeSwingset(config, [], hostStorage, initOpts);
+  const c = await makeSwingsetController(hostStorage, {}, runtimeOpts);
   const id44 = await c.validateAndInstallBundle(bundles.vat44Bundle);
   const idRC = await c.validateAndInstallBundle(bundles.vatRefcountBundle);
   c.pinVatRoot('bootstrap');