diff --git a/packages/SwingSet/tools/bootstrap-relay.js b/packages/SwingSet/tools/bootstrap-relay.js
index a1182e5fbbb..6fa802b397e 100644
--- a/packages/SwingSet/tools/bootstrap-relay.js
+++ b/packages/SwingSet/tools/bootstrap-relay.js
@@ -1,6 +1,7 @@
 import { assert } from '@agoric/assert';
 import { objectMap } from '@agoric/internal';
 import { Far, E } from '@endo/far';
+import { makePromiseKit } from '@endo/promise-kit';
 import { buildManualTimer } from './manual-timer.js';
 
 const { Fail, quote: q } = assert;
@@ -80,6 +81,12 @@ export const buildRootObject = () => {
       return remotable;
     },
 
+    makePromiseKit: () => {
+      const { promise, ...resolverMethods } = makePromiseKit();
+      const resolver = Far('resolver', resolverMethods);
+      return harden({ promise, resolver });
+    },
+
     /**
      * Returns a copy of a remotable's logs.
      *
diff --git a/packages/boot/test/upgrading/upgrade-vats.test.js b/packages/boot/test/upgrading/upgrade-vats.test.js
index b3543b9332f..209b8d5b3e6 100644
--- a/packages/boot/test/upgrading/upgrade-vats.test.js
+++ b/packages/boot/test/upgrading/upgrade-vats.test.js
@@ -473,11 +473,13 @@ test('upgrade vat-vow', async t => {
     promiseFulfilled: ['hello'],
     promiseRejected: ['goodbye', true],
   };
+  const promiseKit = await EV.vat('bootstrap').makePromiseKit();
   const localVows = {
     vowForever: [],
     vowFulfilled: ['hello'],
     vowRejected: ['goodbye', true],
     vowPostUpgrade: [],
+    vowExternalPromise: [promiseKit.promise],
     vowPromiseForever: [undefined, false, true],
   };
   await EV(vowRoot).makeLocalPromiseWatchers(localPromises);
@@ -496,6 +498,10 @@ test('upgrade vat-vow', async t => {
       status: 'unsettled',
       resolver: {},
     },
+    vowExternalPromise: {
+      status: 'unsettled',
+      resolver: {},
+    },
     vowPromiseForever: {
       status: 'unsettled',
       resolver: {},
@@ -512,6 +518,7 @@ test('upgrade vat-vow', async t => {
     vowPostUpgrade: ['bonjour'],
   };
   await EV(vowRoot).resolveVowWatchers(localVowsUpdates);
+  await EV(promiseKit.resolver).resolve('ciao');
   t.deepEqual(dataOnly(await EV(vowRoot).getWatcherResults()), {
     promiseForever: {
       status: 'rejected',
@@ -530,6 +537,7 @@ test('upgrade vat-vow', async t => {
     vowFulfilled: { status: 'fulfilled', value: 'hello' },
     vowRejected: { status: 'rejected', reason: 'goodbye' },
     vowPostUpgrade: { status: 'fulfilled', value: 'bonjour' },
+    vowExternalPromise: { status: 'fulfilled', value: 'ciao' },
     vowPromiseForever: {
       status: 'rejected',
       reason: {