diff --git a/packages/SwingSet/test/snapshots/xsnap-store.test.js.md b/packages/SwingSet/test/snapshots/xsnap-store.test.js.md
index db827766e84..52a1b44b201 100644
--- a/packages/SwingSet/test/snapshots/xsnap-store.test.js.md
+++ b/packages/SwingSet/test/snapshots/xsnap-store.test.js.md
@@ -20,8 +20,8 @@ Generated by [AVA](https://avajs.dev).
     {
       compressSeconds: 0,
       dbSaveSeconds: 0,
-      hash: 'bd10d954d29157e1ab9a068b6bdeb8bb7157489e11dc71b2961f4cab9a7d135c',
-      uncompressedSize: 827051,
+      hash: '30d2d6ce649f1f3b9d5dd48404ee32c4ff0cc9935b7aa4498c0bcd218eedca71',
+      uncompressedSize: 827651,
     }
 
 > after use of harden() - sensitive to SES-shim, XS, and supervisor
@@ -29,6 +29,6 @@ Generated by [AVA](https://avajs.dev).
     {
       compressSeconds: 0,
       dbSaveSeconds: 0,
-      hash: 'ba3a51da404ab14b6366df8966df683bc4f8ffd99f2dc12aabfa3b7728f39952',
-      uncompressedSize: 827211,
+      hash: '46d4988aa5eed7354684b76362fa8b6049e4467139e064a5b73fa8e80bed26a7',
+      uncompressedSize: 827811,
     }
diff --git a/packages/SwingSet/test/snapshots/xsnap-store.test.js.snap b/packages/SwingSet/test/snapshots/xsnap-store.test.js.snap
index 1c7da1cef30..566a5d8b811 100644
Binary files a/packages/SwingSet/test/snapshots/xsnap-store.test.js.snap and b/packages/SwingSet/test/snapshots/xsnap-store.test.js.snap differ
diff --git a/patches/@endo+lockdown+1.0.7.patch b/patches/@endo+lockdown+1.0.7.patch
new file mode 100644
index 00000000000..819e4c9dcac
--- /dev/null
+++ b/patches/@endo+lockdown+1.0.7.patch
@@ -0,0 +1,13 @@
+diff --git a/node_modules/@endo/lockdown/commit-debug.js b/node_modules/@endo/lockdown/commit-debug.js
+index 9595aa0..03e02a2 100644
+--- a/node_modules/@endo/lockdown/commit-debug.js
++++ b/node_modules/@endo/lockdown/commit-debug.js
+@@ -21,7 +21,7 @@ lockdown({
+   // NOTE TO REVIEWERS: If you see the following line commented out,
+   // this may be a development accident that should be fixed before merging.
+   //
+-  errorTaming: 'unsafe',
++  errorTaming: 'unsafe-debug',
+ 
+   // The default `{stackFiltering: 'concise'}` setting usually makes for a
+   // better debugging experience, by severely reducing the noisy distractions
diff --git a/patches/ses+1.5.0.patch b/patches/ses+1.5.0.patch
new file mode 100644
index 00000000000..b2c37f96972
--- /dev/null
+++ b/patches/ses+1.5.0.patch
@@ -0,0 +1,167 @@
+diff --git a/node_modules/ses/src/error/tame-error-constructor.js b/node_modules/ses/src/error/tame-error-constructor.js
+index 2788c42..db59952 100644
+--- a/node_modules/ses/src/error/tame-error-constructor.js
++++ b/node_modules/ses/src/error/tame-error-constructor.js
+@@ -7,6 +7,7 @@ import {
+   setPrototypeOf,
+   getOwnPropertyDescriptor,
+   defineProperty,
++  getOwnPropertyDescriptors,
+ } from '../commons.js';
+ import { NativeErrors } from '../permits.js';
+ import { tameV8ErrorConstructor } from './tame-v8-error-constructor.js';
+@@ -29,12 +30,17 @@ const tamedMethods = {
+     return '';
+   },
+ };
++let initialGetStackString = tamedMethods.getStackString;
+ 
+ export default function tameErrorConstructor(
+   errorTaming = 'safe',
+   stackFiltering = 'concise',
+ ) {
+-  if (errorTaming !== 'safe' && errorTaming !== 'unsafe') {
++  if (
++    errorTaming !== 'safe' &&
++    errorTaming !== 'unsafe' &&
++    errorTaming !== 'unsafe-debug'
++  ) {
+     throw TypeError(`unrecognized errorTaming ${errorTaming}`);
+   }
+   if (stackFiltering !== 'concise' && stackFiltering !== 'verbose') {
+@@ -42,9 +48,9 @@ export default function tameErrorConstructor(
+   }
+   const ErrorPrototype = FERAL_ERROR.prototype;
+ 
+-  const platform =
+-    typeof FERAL_ERROR.captureStackTrace === 'function' ? 'v8' : 'unknown';
+   const { captureStackTrace: originalCaptureStackTrace } = FERAL_ERROR;
++  const platform =
++    typeof originalCaptureStackTrace === 'function' ? 'v8' : 'unknown';
+ 
+   const makeErrorConstructor = (_ = {}) => {
+     // eslint-disable-next-line no-shadow
+@@ -122,6 +128,45 @@ export default function tameErrorConstructor(
+     },
+   });
+ 
++  if (errorTaming === 'unsafe-debug' && platform === 'v8') {
++    // This case is a kludge to work around
++    // https://github.com/endojs/endo/issues/1798
++    // https://github.com/endojs/endo/issues/2348
++    // https://github.com/Agoric/agoric-sdk/issues/8662
++
++    defineProperties(InitialError, {
++      prepareStackTrace: {
++        get() {
++          return FERAL_ERROR.prepareStackTrace;
++        },
++        set(newPrepareStackTrace) {
++          FERAL_ERROR.prepareStackTrace = newPrepareStackTrace;
++        },
++        enumerable: false,
++        configurable: true,
++      },
++      captureStackTrace: {
++        value: FERAL_ERROR.captureStackTrace,
++        writable: true,
++        enumerable: false,
++        configurable: true,
++      },
++    });
++
++    const descs = getOwnPropertyDescriptors(InitialError);
++    defineProperties(SharedError, {
++      stackTraceLimit: descs.stackTraceLimit,
++      prepareStackTrace: descs.prepareStackTrace,
++      captureStackTrace: descs.captureStackTrace,
++    });
++
++    return {
++      '%InitialGetStackString%': initialGetStackString,
++      '%InitialError%': InitialError,
++      '%SharedError%': SharedError,
++    };
++  }
++
+   // The default SharedError much be completely powerless even on v8,
+   // so the lenient `stackTraceLimit` accessor does nothing on all
+   // platforms.
+@@ -171,7 +216,6 @@ export default function tameErrorConstructor(
+     });
+   }
+ 
+-  let initialGetStackString = tamedMethods.getStackString;
+   if (platform === 'v8') {
+     initialGetStackString = tameV8ErrorConstructor(
+       FERAL_ERROR,
+@@ -179,7 +223,7 @@ export default function tameErrorConstructor(
+       errorTaming,
+       stackFiltering,
+     );
+-  } else if (errorTaming === 'unsafe') {
++  } else if (errorTaming === 'unsafe' || errorTaming === 'unsafe-debug') {
+     // v8 has too much magic around their 'stack' own property for it to
+     // coexist cleanly with this accessor. So only install it on non-v8
+ 
+diff --git a/node_modules/ses/src/lockdown.js b/node_modules/ses/src/lockdown.js
+index 107b5d0..dd709e5 100644
+--- a/node_modules/ses/src/lockdown.js
++++ b/node_modules/ses/src/lockdown.js
+@@ -58,7 +58,7 @@ import { tameFauxDataProperties } from './tame-faux-data-properties.js';
+ 
+ /** @import {LockdownOptions} from '../types.js' */
+ 
+-const { Fail, details: d, quote: q } = assert;
++const { Fail, details: X, quote: q } = assert;
+ 
+ /** @type {Error=} */
+ let priorRepairIntrinsics;
+@@ -200,7 +200,7 @@ export const repairIntrinsics = (options = {}) => {
+   priorRepairIntrinsics === undefined ||
+     // eslint-disable-next-line @endo/no-polymorphic-call
+     assert.fail(
+-      d`Already locked down at ${priorRepairIntrinsics} (SES_ALREADY_LOCKED_DOWN)`,
++      X`Already locked down at ${priorRepairIntrinsics} (SES_ALREADY_LOCKED_DOWN)`,
+       TypeError,
+     );
+   // See https://github.com/endojs/endo/blob/master/packages/ses/error-codes/SES_ALREADY_LOCKED_DOWN.md
+@@ -298,7 +298,7 @@ export const repairIntrinsics = (options = {}) => {
+    * @type {((error: any) => string | undefined) | undefined}
+    */
+   let optGetStackString;
+-  if (errorTaming !== 'unsafe') {
++  if (errorTaming === 'safe') {
+     optGetStackString = intrinsics['%InitialGetStackString%'];
+   }
+   const consoleRecord = tameConsole(
+@@ -318,13 +318,17 @@ export const repairIntrinsics = (options = {}) => {
+     // There doesn't seem to be a cleaner way to reach it.
+     hostIntrinsics.SafeMap = getPrototypeOf(
+       // eslint-disable-next-line no-underscore-dangle
+-      /** @type {any} */ (consoleRecord.console)._times,
++      /** @type {any} */(consoleRecord.console)._times,
+     );
+   }
+ 
+   // @ts-ignore assert is absent on globalThis type def.
+-  if (errorTaming === 'unsafe' && globalThis.assert === assert) {
+-    // If errorTaming is 'unsafe' we replace the global assert with
++  if (
++    (errorTaming === 'unsafe' || errorTaming === 'unsafe-debug') &&
++    globalThis.assert === assert
++  ) {
++    // If errorTaming is 'unsafe' or 'unsafe-debug' we replace the
++    // global assert with
+     // one whose `details` template literal tag does not redact
+     // unmarked substitution values. IOW, it blabs information that
+     // was supposed to be secret from callers, as an aid to debugging
+@@ -391,7 +395,7 @@ export const repairIntrinsics = (options = {}) => {
+     priorHardenIntrinsics === undefined ||
+       // eslint-disable-next-line @endo/no-polymorphic-call
+       assert.fail(
+-        d`Already locked down at ${priorHardenIntrinsics} (SES_ALREADY_LOCKED_DOWN)`,
++        X`Already locked down at ${priorHardenIntrinsics} (SES_ALREADY_LOCKED_DOWN)`,
+         TypeError,
+       );
+     // See https://github.com/endojs/endo/blob/master/packages/ses/error-codes/SES_ALREADY_LOCKED_DOWN.md