diff --git a/packages/zoe/src/contractFacet/internal-types.js b/packages/zoe/src/contractFacet/internal-types.js
index 7991eb864300..a4973a904961 100644
--- a/packages/zoe/src/contractFacet/internal-types.js
+++ b/packages/zoe/src/contractFacet/internal-types.js
@@ -16,7 +16,7 @@
 
 /**
  * @typedef ZCFZygote
- * @property {(bundle: SourceBundle) => void} evaluateContract
+ * @property {(bundleOrBundleCap: SourceBundle | BundleCap) => void} evaluateContract
  * @property {(instanceAdminFromZoe: ERef<ZoeInstanceAdmin>,
  *     instanceRecordFromZoe: InstanceRecord,
  *     issuerStorageFromZoe: IssuerRecords,
diff --git a/packages/zoe/src/contractFacet/vatRoot.js b/packages/zoe/src/contractFacet/vatRoot.js
index e4b3a8b336cd..3331e4d7029f 100644
--- a/packages/zoe/src/contractFacet/vatRoot.js
+++ b/packages/zoe/src/contractFacet/vatRoot.js
@@ -29,7 +29,7 @@ export function buildRootObject(powers, _params, testJigSetter = undefined) {
 
   /** @type {ExecuteContract} */
   const executeContract = (
-    bundle,
+    bundleOrBundleCap,
     zoeService,
     invitationIssuer,
     zoeInstanceAdmin,
@@ -44,7 +44,7 @@ export function buildRootObject(powers, _params, testJigSetter = undefined) {
       invitationIssuer,
       testJigSetter,
     );
-    zcfZygote.evaluateContract(bundle);
+    zcfZygote.evaluateContract(bundleOrBundleCap);
     return zcfZygote.startContract(
       zoeInstanceAdmin,
       instanceRecordFromZoe,
diff --git a/packages/zoe/src/contractFacet/zcfZygote.js b/packages/zoe/src/contractFacet/zcfZygote.js
index c7f657facf72..32540606142c 100644
--- a/packages/zoe/src/contractFacet/zcfZygote.js
+++ b/packages/zoe/src/contractFacet/zcfZygote.js
@@ -2,7 +2,7 @@
 
 import { assert, details as X, makeAssert } from '@agoric/assert';
 import { E } from '@agoric/eventual-send';
-import { Far, Remotable } from '@endo/marshal';
+import { Far, Remotable, passStyleOf } from '@endo/marshal';
 import { AssetKind, AmountMath } from '@agoric/ertp';
 import { makeNotifierKit, observeNotifier } from '@agoric/notifier';
 import { makePromiseKit } from '@endo/promise-kit';
@@ -275,7 +275,6 @@ export const makeZCFZygote = (
     shutdown: completion => {
       E(zoeInstanceAdmin).exitAllSeats(completion);
       dropAllReferences();
-      // @ts-ignore powers is not typed correctly: https://github.com/Agoric/agoric-sdk/issues/3239s
       powers.exitVat(completion);
     },
     shutdownWithFailure,
@@ -340,7 +339,15 @@ export const makeZCFZygote = (
    * @type {ZCFZygote}
    * */
   const zcfZygote = {
-    evaluateContract: bundle => {
+    evaluateContract: bundleOrBundleCap => {
+      let bundle;
+      if (passStyleOf(bundleOrBundleCap) === 'remotable') {
+        const bundleCap = bundleOrBundleCap;
+        // @ts-expect-error vatPowers is not typed correctly: https://github.com/Agoric/agoric-sdk/issues/3239
+        bundle = powers.D(bundleCap).getBundle();
+      } else {
+        bundle = bundleOrBundleCap;
+      }
       contractCode = evalContractBundle(bundle);
       handlePWarning(contractCode);
     },
diff --git a/packages/zoe/src/zoeService/installationStorage.js b/packages/zoe/src/zoeService/installationStorage.js
index 2846c5541f2f..f188ba41e590 100644
--- a/packages/zoe/src/zoeService/installationStorage.js
+++ b/packages/zoe/src/zoeService/installationStorage.js
@@ -3,49 +3,85 @@
 import { assert, details as X } from '@agoric/assert';
 import { Far } from '@endo/marshal';
 import { E } from '@agoric/eventual-send';
+import { makeWeakStore } from '@agoric/store';
+
+/** @typedef { import('@agoric/swingset-vat').BundleID} BundleID */
 
 /**
- *
+ * @param {GetBundleCapForID} getBundleCapForID
  */
-export const makeInstallationStorage = () => {
-  /** @type {WeakSet<Installation>} */
-  const installations = new WeakSet();
+export const makeInstallationStorage = getBundleCapForID => {
+  /** @type {WeakStore<Installation, { bundleCap: BundleCap, bundleID: BundleID }>} */
+  const installationsBundleCap = makeWeakStore('installationsBundleCap');
+  /** @type {WeakStore<Installation, SourceBundle>} */
+  const installationsBundle = makeWeakStore('installationsBundle');
 
   /**
-   * Create an installation by permanently storing the bundle. The code is
-   * currently evaluated each time it is used to make a new instance of a
-   * contract. When SwingSet supports zygotes, the code will be evaluated once
-   * when creating a zcfZygote, then the start() function will be called each
-   * time an instance is started.
+   * Create an installation from a bundle ID or a full bundle. If we are
+   * given a bundle ID, wait for the corresponding code bundle to be received
+   * by the swingset kernel, then store its bundlecap. The code is currently
+   * evaluated each time it is used to make a new instance of a contract.
+   * When SwingSet supports zygotes, the code will be evaluated once when
+   * creating a zcfZygote, then the start() function will be called each time
+   * an instance is started.
    */
-  /** @type {Install} */
-  const install = async bundle => {
-    assert.typeof(bundle, 'object', X`a bundle must be provided`);
+
+  /** @type {InstallBundle} */
+  const installBundle = async bundle => {
+    assert.typeof(bundle, 'object', 'a bundle must be provided');
     /** @type {Installation} */
     const installation = Far('Installation', {
       getBundle: () => bundle,
     });
-    installations.add(installation);
+    installationsBundle.init(installation, bundle);
     return installation;
   };
 
-  const assertInstallation = installation =>
-    assert(
-      installations.has(installation),
-      X`${installation} was not a valid installation`,
-    );
+  /** @type {InstallBundleID} */
+  const installBundleID = async bundleID => {
+    assert.typeof(bundleID, 'string', `a bundle ID must be provided`);
+    // this waits until someone tells the host application to store the
+    // bundle into the kernel, with controller.validateAndInstallBundle()
+    const bundleCap = await getBundleCapForID(bundleID);
+    // AWAIT
+
+    /** @type {Installation} */
+    const installation = Far('Installation', {
+      getBundle: () => {
+        throw Error('bundleID-based Installation');
+      },
+    });
+    installationsBundleCap.init(installation, { bundleCap, bundleID });
+    return installation;
+  };
 
   /** @type {UnwrapInstallation} */
   const unwrapInstallation = installationP => {
     return E.when(installationP, installation => {
-      assertInstallation(installation);
-      const bundle = installation.getBundle();
-      return { bundle, installation };
+      if (installationsBundleCap.has(installation)) {
+        const { bundleCap, bundleID } =
+          installationsBundleCap.get(installation);
+        return { bundleCap, bundleID, installation };
+      } else if (installationsBundle.has(installation)) {
+        const bundle = installationsBundle.get(installation);
+        return { bundle, installation };
+      } else {
+        assert.fail(X`${installation} was not a valid installation`);
+      }
     });
   };
 
+  const getBundleIDFromInstallation = async allegedInstallationP => {
+    const { bundleID } = await unwrapInstallation(allegedInstallationP);
+    // AWAIT
+    assert(bundleID, 'installation does not have a bundle ID');
+    return bundleID;
+  };
+
   return harden({
-    install,
+    installBundle,
+    installBundleID,
     unwrapInstallation,
+    getBundleIDFromInstallation,
   });
 };
diff --git a/packages/zoe/src/zoeService/internal-types.js b/packages/zoe/src/zoeService/internal-types.js
index 9ead46bc8c53..767ad6a6142f 100644
--- a/packages/zoe/src/zoeService/internal-types.js
+++ b/packages/zoe/src/zoeService/internal-types.js
@@ -56,12 +56,14 @@
 /**
  * @callback UnwrapInstallation
  *
- * Assert the installation is known, and return the bundle and
+ * Assert the installation is known, and return the bundle/bundlecap and
  * installation
  *
  * @param {ERef<Installation>} installationP
  * @returns {Promise<{
- *   bundle: SourceBundle,
+ *   bundle?: SourceBundle,
+ *   bundleCap?: BundleCap,
+ *   bundleID?: BundleID,
  *   installation:Installation
  * }>}
  */
@@ -105,13 +107,21 @@
  * @returns {ZoeInstanceStorageManager}
  */
 
+/**
+ * @callback GetBundleCapForID
+ * @param {BundleID} id
+ * @returns {Promise<BundleCap>}
+ */
+
 /**
  * @typedef ZoeStorageManager
  * @property {MakeZoeInstanceStorageManager} makeZoeInstanceStorageManager
  * @property {GetAssetKindByBrand} getAssetKindByBrand
  * @property {DepositPayments} depositPayments
  * @property {Issuer} invitationIssuer
- * @property {Install} install
+ * @property {InstallBundle} installBundle
+ * @property {InstallBundleID} installBundleID
+ * @property {GetBundleIDFromInstallation} getBundleIDFromInstallation
  * @property {GetPublicFacet} getPublicFacet
  * @property {GetBrands} getBrands
  * @property {GetIssuers} getIssuers
diff --git a/packages/zoe/src/zoeService/startInstance.js b/packages/zoe/src/zoeService/startInstance.js
index a95726e569ce..6d4558f85d86 100644
--- a/packages/zoe/src/zoeService/startInstance.js
+++ b/packages/zoe/src/zoeService/startInstance.js
@@ -31,9 +31,14 @@ export const makeStartInstance = (
     /** @type {WeakStore<SeatHandle, ZoeSeatAdmin>} */
     const seatHandleToZoeSeatAdmin = makeWeakStore('seatHandle');
 
-    const { installation, bundle } = await unwrapInstallation(installationP);
+    const { installation, bundle, bundleCap } = await unwrapInstallation(
+      installationP,
+    );
     // AWAIT ///
 
+    const bundleOrBundleCap = bundle || bundleCap;
+    assert(bundleOrBundleCap);
+
     if (privateArgs !== undefined) {
       const passStyle = passStyleOf(privateArgs);
       assert(
@@ -204,7 +209,7 @@ export const makeStartInstance = (
       creatorInvitation: creatorInvitationP,
       handleOfferObj,
     } = await E(zcfRoot).executeContract(
-      bundle,
+      bundleOrBundleCap,
       zoeServicePromise,
       zoeInstanceStorageManager.invitationIssuer,
       zoeInstanceAdminForZcf,
diff --git a/packages/zoe/src/zoeService/types.js b/packages/zoe/src/zoeService/types.js
index b9c7ce6051cb..ef719369dd56 100644
--- a/packages/zoe/src/zoeService/types.js
+++ b/packages/zoe/src/zoeService/types.js
@@ -25,6 +25,7 @@
  * a smart contract in particular ways.
  *
  * @property {Install} install
+ * @property {InstallBundleID} installBundleID
  * @property {StartInstance} startInstance
  * @property {Offer} offer
  * @property {GetPublicFacet} getPublicFacet
@@ -45,6 +46,7 @@
  * Deprecated. Does nothing useful but provided during transition so less old
  * code breaks.
  * @property {GetConfiguration} getConfiguration
+ * @property {GetBundleIDFromInstallation} getBundleIDFromInstallation
  */
 
 /**
@@ -113,15 +115,34 @@
  */
 
 /**
- * @callback Install
+ * @callback InstallBundle
  *
  * Create an installation by safely evaluating the code and
  * registering it with Zoe. Returns an installation.
  *
- * @param {SourceBundle} bundle
+ * @param {Bundle} bundle
  * @returns {Promise<Installation>}
  */
 
+/**
+ * @callback InstallBundleID
+ *
+ * Create an installation from a Bundle ID. Returns an installation.
+ *
+ * @param {BundleID} bundleID
+ * @returns {Promise<Installation>}
+ */
+
+/**
+ * @callback GetBundleIDFromInstallation
+ *
+ * Verify that an alleged Invitation is real, and return the Bundle ID it
+ * will use for contract code.
+ *
+ * @param {ERef<Installation>}
+ * @returns {Promise<BundleID>}
+ */
+
 /**
  * @callback StartInstance
  *
@@ -268,9 +289,9 @@
 
 /**
  * @typedef {Object} VatAdminSvc
- * @property {(BundleID: id) => BundleCap} getBundleCap
- * @property {(name: string) => BundleCap} getNamedBundleCap
- * @property {(bundleCap: BundleCap) => RootAndAdminNode} createVat
+ * @property {(BundleID: id) => Promise<BundleCap>} getBundleCap
+ * @property {(name: string) => Promise<BundleCap>} getNamedBundleCap
+ * @property {(bundleCap: BundleCap) => Promise<RootAndAdminNode>} createVat
  */
 
 /**
diff --git a/packages/zoe/src/zoeService/zoe.js b/packages/zoe/src/zoeService/zoe.js
index b150cbc4005a..9aed604ac265 100644
--- a/packages/zoe/src/zoeService/zoe.js
+++ b/packages/zoe/src/zoeService/zoe.js
@@ -16,6 +16,7 @@ import '../../exported.js';
 import '../internal-types.js';
 
 import { AssetKind } from '@agoric/ertp';
+import { E } from '@agoric/eventual-send';
 import { Far } from '@endo/marshal';
 import { makePromiseKit } from '@endo/promise-kit';
 
@@ -61,6 +62,8 @@ const makeZoeKit = (
     shutdownZoeVat,
   );
 
+  const getBundleCapFromID = bundleID => E(vatAdminSvc).getBundleCap(bundleID);
+
   // This method contains the power to create a new ZCF Vat, and must
   // be closely held. vatAdminSvc is even more powerful - any vat can
   // be created. We severely restrict access to vatAdminSvc for this reason.
@@ -72,8 +75,10 @@ const makeZoeKit = (
     depositPayments,
     getAssetKindByBrand,
     makeZoeInstanceStorageManager,
-    install,
+    installBundle,
+    installBundleID,
     unwrapInstallation,
+    getBundleIDFromInstallation,
     getPublicFacet,
     getBrands,
     getIssuers,
@@ -83,6 +88,7 @@ const makeZoeKit = (
     invitationIssuer,
   } = makeZoeStorageManager(
     createZCFVat,
+    getBundleCapFromID,
     getFeeIssuerKit,
     shutdownZoeVat,
     feeIssuer,
@@ -117,7 +123,8 @@ const makeZoeKit = (
 
   /** @type {ZoeService} */
   const zoeService = Far('zoeService', {
-    install,
+    install: installBundle,
+    installBundleID,
     startInstance,
     offer,
     /**
@@ -145,6 +152,7 @@ const makeZoeKit = (
     getInstallation,
     getInvitationDetails,
     getConfiguration,
+    getBundleIDFromInstallation,
   });
 
   // startInstance must pass the ZoeService to the newly created ZCF
diff --git a/packages/zoe/src/zoeService/zoeStorageManager.js b/packages/zoe/src/zoeService/zoeStorageManager.js
index bd634eab054f..73090058bb75 100644
--- a/packages/zoe/src/zoeService/zoeStorageManager.js
+++ b/packages/zoe/src/zoeService/zoeStorageManager.js
@@ -26,6 +26,7 @@ import { makeInstallationStorage } from './installationStorage.js';
  *
  * @param {CreateZCFVat} createZCFVat - the ability to create a new
  * ZCF Vat
+ * @param {GetBundleCapForID} getBundleCapForID
  * @param {GetFeeIssuerKit} getFeeIssuerKit
  * @param {ShutdownWithFailure} shutdownZoeVat
  * @param {Issuer} feeIssuer
@@ -34,6 +35,7 @@ import { makeInstallationStorage } from './installationStorage.js';
  */
 export const makeZoeStorageManager = (
   createZCFVat,
+  getBundleCapForID,
   getFeeIssuerKit,
   shutdownZoeVat,
   feeIssuer,
@@ -82,7 +84,12 @@ export const makeZoeStorageManager = (
   // Zoe stores "installations" - identifiable bundles of contract
   // code that can be reused again and again to create new contract
   // instances
-  const { install, unwrapInstallation } = makeInstallationStorage();
+  const {
+    installBundle,
+    installBundleID,
+    unwrapInstallation,
+    getBundleIDFromInstallation,
+  } = makeInstallationStorage(getBundleCapForID);
 
   /** @type {MakeZoeInstanceStorageManager} */
   const makeZoeInstanceStorageManager = async (
@@ -237,7 +244,9 @@ export const makeZoeStorageManager = (
     getAssetKindByBrand: issuerStorage.getAssetKindByBrand,
     depositPayments: escrowStorage.depositPayments,
     invitationIssuer,
-    install,
+    installBundle,
+    installBundleID,
+    getBundleIDFromInstallation,
     getPublicFacet,
     getBrands,
     getIssuers,
diff --git a/packages/zoe/test/unitTests/setupBasicMints.js b/packages/zoe/test/unitTests/setupBasicMints.js
index f734122556f9..ad37c6f9f91e 100644
--- a/packages/zoe/test/unitTests/setupBasicMints.js
+++ b/packages/zoe/test/unitTests/setupBasicMints.js
@@ -3,7 +3,7 @@
 import { makeIssuerKit, AmountMath } from '@agoric/ertp';
 import { makeStore } from '@agoric/store';
 import { makeZoeKit } from '../../src/zoeService/zoe.js';
-import fakeVatAdmin from '../../tools/fakeVatAdmin.js';
+import { makeFakeVatAdmin } from '../../tools/fakeVatAdmin.js';
 
 const setup = () => {
   const moolaBundle = makeIssuerKit('moola');
@@ -21,6 +21,7 @@ const setup = () => {
     brands.init(k, allBundles[k].brand);
   }
 
+  const { admin: fakeVatAdmin, vatAdminState } = makeFakeVatAdmin();
   const { zoeService: zoe } = makeZoeKit(fakeVatAdmin);
 
   /** @type {(brand: Brand) => (value: AmountValue) => Amount} */
@@ -45,6 +46,7 @@ const setup = () => {
    * @property {(value: AmountValue) => Amount} simoleans
    * @property {(value: AmountValue) => Amount} bucks
    * @property {ERef<ZoeService>} zoe
+   * @property {*} vatAdminState
    */
 
   /** @type {BasicMints} */
@@ -66,6 +68,7 @@ const setup = () => {
     simoleans: makeSimpleMake(simoleanBundle.brand),
     bucks: makeSimpleMake(bucksBundle.brand),
     zoe,
+    vatAdminState,
   };
   harden(result);
   return result;
diff --git a/packages/zoe/test/unitTests/test-zoe.js b/packages/zoe/test/unitTests/test-zoe.js
index 8f2bc9cbf97d..5706b5fc7c74 100644
--- a/packages/zoe/test/unitTests/test-zoe.js
+++ b/packages/zoe/test/unitTests/test-zoe.js
@@ -41,16 +41,34 @@ test(`E(zoe).install bad bundle`, async t => {
   });
 });
 
-test(`E(zoe).install`, async t => {
+test(`E(zoe).install(bundle)`, async t => {
   const { zoe } = setup();
   const contractPath = `${dirname}/../../src/contracts/atomicSwap`;
   const bundle = await bundleSource(contractPath);
   const installation = await E(zoe).install(bundle);
+  t.is(passStyleOf(installation), 'remotable');
+});
+
+test(`E(zoe).installBundleID bad id`, async t => {
+  const { zoe } = setup();
+  // @ts-ignore deliberate invalid arguments for testing
+  await t.throwsAsync(() => E(zoe).installBundleID(), {
+    message: 'a bundle ID must be provided',
+  });
+});
+
+test(`E(zoe).installBundleID(bundleID)`, async t => {
+  const { zoe, vatAdminState } = setup();
+  const contractPath = `${dirname}/../../src/contracts/atomicSwap`;
+  const bundle = await bundleSource(contractPath);
+  vatAdminState.installBundle('b1-atomic', bundle);
+  const installation = await E(zoe).installBundleID('b1-atomic');
   // TODO Check the integrity of the installation by its hash.
   // https://github.com/Agoric/agoric-sdk/issues/3859
   // const hash = await E(installation).getHash();
   // assert.is(hash, 'XXX');
-  t.is(await E(installation).getBundle(), bundle);
+  // NOTE: the bundle ID is now the hash
+  t.is(await E(zoe).getBundleIDFromInstallation(installation), 'b1-atomic');
 });
 
 test(`E(zoe).startInstance bad installation`, async t => {
diff --git a/packages/zoe/test/unitTests/zoe/test-installationStorage.js b/packages/zoe/test/unitTests/zoe/test-installationStorage.js
index e59f00c243cd..3c5abe334abe 100644
--- a/packages/zoe/test/unitTests/zoe/test-installationStorage.js
+++ b/packages/zoe/test/unitTests/zoe/test-installationStorage.js
@@ -3,49 +3,67 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 import { test } from '@agoric/zoe/tools/prepare-test-env-ava.js';
 
+import { makeHandle } from '../../../src/makeHandle.js';
 import { makeInstallationStorage } from '../../../src/zoeService/installationStorage.js';
 
 test('install, unwrap installations', async t => {
-  const { install, unwrapInstallation } = makeInstallationStorage();
+  const { installBundle, unwrapInstallation } = makeInstallationStorage();
   const fakeBundle = {};
 
-  const installation = await install(fakeBundle);
+  const installation = await installBundle(fakeBundle);
   const unwrapped = await unwrapInstallation(installation);
   t.is(unwrapped.installation, installation);
   t.is(unwrapped.bundle, fakeBundle);
 });
 
+test('install, unwrap installation of bundlecap', async t => {
+  const bundleCaps = { id: makeHandle('BundleCap') };
+  const getBundleCapFromID = id => bundleCaps[id];
+
+  const { installBundleID, unwrapInstallation } =
+    makeInstallationStorage(getBundleCapFromID);
+
+  const installation = await installBundleID('id');
+  const unwrapped = await unwrapInstallation(installation);
+  t.is(unwrapped.installation, installation);
+  t.is(unwrapped.bundleID, 'id');
+  t.is(unwrapped.bundleCap, bundleCaps.id);
+});
+
 test('unwrap promise for installation', async t => {
-  const { install, unwrapInstallation } = makeInstallationStorage();
+  const { installBundle, unwrapInstallation } = makeInstallationStorage();
   const fakeBundle = {};
 
-  const installation = await install(fakeBundle);
+  const installation = await installBundle(fakeBundle);
   const unwrapped = await unwrapInstallation(Promise.resolve(installation));
   t.is(unwrapped.installation, installation);
   t.is(unwrapped.bundle, fakeBundle);
 });
 
 test('install several', async t => {
-  const { install, unwrapInstallation } = makeInstallationStorage();
+  const { installBundle, unwrapInstallation } = makeInstallationStorage();
   const fakeBundle1 = {};
   const fakeBundle2 = {};
 
-  const installation1 = await install(fakeBundle1);
+  const installation1 = await installBundle(fakeBundle1);
   const unwrapped1 = await unwrapInstallation(installation1);
   t.is(unwrapped1.installation, installation1);
   t.is(unwrapped1.bundle, fakeBundle1);
 
-  const installation2 = await install(fakeBundle2);
+  const installation2 = await installBundle(fakeBundle2);
   const unwrapped2 = await unwrapInstallation(installation2);
   t.is(unwrapped2.installation, installation2);
   t.is(unwrapped2.bundle, fakeBundle2);
 });
 
 test('install same twice', async t => {
-  const { install, unwrapInstallation } = makeInstallationStorage();
+  const bundleCaps = { id: makeHandle('BundleCap') };
+  const getBundleCapFromID = id => bundleCaps[id];
+  const { installBundle, installBundleID, unwrapInstallation } =
+    makeInstallationStorage(getBundleCapFromID);
   const fakeBundle1 = {};
 
-  const installation1 = await install(fakeBundle1);
+  const installation1 = await installBundle(fakeBundle1);
   const unwrapped1 = await unwrapInstallation(installation1);
   t.is(unwrapped1.installation, installation1);
   t.is(unwrapped1.bundle, fakeBundle1);
@@ -53,9 +71,22 @@ test('install same twice', async t => {
   // If the same bundle is installed twice, the bundle is the same,
   // but the installation is different. Zoe does not currently care about
   // duplicate bundles.
-  const installation2 = await install(fakeBundle1);
+  const installation2 = await installBundle(fakeBundle1);
   const unwrapped2 = await unwrapInstallation(installation2);
   t.is(unwrapped2.installation, installation2);
   t.not(installation2, installation1);
   t.is(unwrapped2.bundle, fakeBundle1);
+
+  // same for bundleIDs
+  const installation3 = await installBundleID('id');
+  const installation4 = await installBundleID('id');
+  t.not(installation3, installation4);
+  const unwrapped3 = await unwrapInstallation(installation3);
+  t.is(unwrapped3.installation, installation3);
+  t.is(unwrapped3.bundleID, 'id');
+  t.is(unwrapped3.bundleCap, bundleCaps.id);
+  const unwrapped4 = await unwrapInstallation(installation4);
+  t.is(unwrapped4.installation, installation4);
+  t.is(unwrapped4.bundleID, 'id');
+  t.is(unwrapped4.bundleCap, bundleCaps.id);
 });
diff --git a/packages/zoe/tools/fakeVatAdmin.js b/packages/zoe/tools/fakeVatAdmin.js
index 2088c3988390..eec1f6fb3508 100644
--- a/packages/zoe/tools/fakeVatAdmin.js
+++ b/packages/zoe/tools/fakeVatAdmin.js
@@ -3,6 +3,7 @@
 import { E } from '@agoric/eventual-send';
 import { makePromiseKit } from '@endo/promise-kit';
 import { Far } from '@endo/marshal';
+import { makeStore } from '@agoric/store';
 
 import { assert } from '@agoric/assert';
 import { evalContractBundle } from '../src/contractFacet/evalContractCode.js';
@@ -10,10 +11,14 @@ import { handlePKitWarning } from '../src/handleWarning.js';
 import { makeHandle } from '../src/makeHandle.js';
 import zcfContractBundle from '../bundles/bundle-contractFacet.js';
 
+/** @typedef { import('@agoric/swingset-vat').BundleID} BundleID */
+/** @typedef { import('@agoric/swingset-vat').EndoZipBase64Bundle} EndoZipBase64Bundle */
+
 // this simulates a bundlecap, which is normally a swingset "device node"
 /** @typedef { import('@agoric/swingset-vat').BundleCap } BundleCap */
-/** @type {BundleCap} */
-export const zcfBundleCap = makeHandle('BundleCap');
+/** @type {() => BundleCap} */
+const fakeBundleCap = () => makeHandle('BundleCap');
+export const zcfBundleCap = fakeBundleCap();
 
 /**
  * @param { (...args) => unknown } [testContextSetter]
@@ -25,6 +30,10 @@ function makeFakeVatAdmin(testContextSetter = undefined, makeRemote = x => x) {
   let exitMessage;
   let hasExited = false;
   let exitWithFailure;
+  /** @type {Store<BundleID, BundleCap>} */
+  const idToBundleCap = makeStore('idToBundleCap');
+  /** @type {Store<BundleCap, EndoZipBase64Bundle>} */
+  const bundleCapToBundle = makeStore('bundleCapToBundle');
   const fakeVatPowers = {
     exitVat: completion => {
       exitMessage = completion;
@@ -36,49 +45,74 @@ function makeFakeVatAdmin(testContextSetter = undefined, makeRemote = x => x) {
       hasExited = true;
       exitWithFailure = true;
     },
+    D: bundleCap => ({
+      getBundle: () => bundleCapToBundle.get(bundleCap),
+    }),
   };
 
   // This is explicitly intended to be mutable so that
   // test-only state can be provided from contracts
   // to their tests.
   const admin = Far('vatAdmin', {
-    getBundleCap: _bundleID => {
-      assert.fail(`fakeVatAdmin.getBundleCap() not yet implemented`);
+    getBundleCap: bundleID => {
+      if (!idToBundleCap.has(bundleID)) {
+        idToBundleCap.init(bundleID, fakeBundleCap());
+      }
+      return Promise.resolve(idToBundleCap.get(bundleID));
     },
     getNamedBundleCap: name => {
       assert.equal(name, 'zcf', 'fakeVatAdmin only knows ZCF');
-      return zcfBundleCap;
+      return Promise.resolve(zcfBundleCap);
     },
     createVat: bundleCap => {
       assert.equal(bundleCap, zcfBundleCap, 'fakeVatAdmin only knows ZCF');
       const bundle = zcfContractBundle;
-      return harden({
-        root: makeRemote(
-          E(evalContractBundle(bundle)).buildRootObject(
-            fakeVatPowers,
-            undefined,
-            testContextSetter,
+      return Promise.resolve(
+        harden({
+          root: makeRemote(
+            E(evalContractBundle(bundle)).buildRootObject(
+              fakeVatPowers,
+              undefined,
+              testContextSetter,
+            ),
           ),
-        ),
-        adminNode: Far('adminNode', {
-          done: () => {
-            const kit = makePromiseKit();
-            handlePKitWarning(kit);
-            return kit.promise;
-          },
-          terminateWithFailure: () => {},
+          adminNode: Far('adminNode', {
+            done: () => {
+              const kit = makePromiseKit();
+              handlePKitWarning(kit);
+              return kit.promise;
+            },
+            terminateWithFailure: () => {},
+          }),
         }),
-      });
+      );
     },
   });
   const vatAdminState = {
     getExitMessage: () => exitMessage,
     getHasExited: () => hasExited,
     getExitWithFailure: () => exitWithFailure,
+    installBundle: (id, bundle) => {
+      if (idToBundleCap.has(id)) {
+        assert.equal(
+          bundle.endoZipBase64,
+          bundleCapToBundle.get(idToBundleCap.get(id)).endoZipBase64,
+        );
+        return;
+      }
+      const bundleCap = fakeBundleCap();
+      idToBundleCap.init(id, bundleCap);
+      bundleCapToBundle.init(bundleCap, bundle);
+    },
   };
   return { admin, vatAdminState };
 }
 
+// Tests which use this global/shared fakeVatAdmin should really import
+// makeFakeVatAdmin() instead, and build their own private instance. This
+// will be forced when #4565 requires them to use
+// vatAdminState.installBundle().
+
 const fakeVatAdmin = makeFakeVatAdmin().admin;
 
 export default fakeVatAdmin;