diff --git a/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js b/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
index fcd84fedfed71..ff8e7e1ac8683 100644
--- a/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
+++ b/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
@@ -1573,7 +1573,6 @@ describe('ReactHooksInspectionIntegration', () => {
   });
 
   describe('useMemoCache', () => {
-    // @gate enableUseMemoCacheHook
     it('should not be inspectable', async () => {
       function Foo() {
         const $ = useMemoCache(1);
@@ -1601,7 +1600,6 @@ describe('ReactHooksInspectionIntegration', () => {
       expect(tree.length).toEqual(0);
     });
 
-    // @gate enableUseMemoCacheHook
     it('should work in combination with other hooks', async () => {
       function useSomething() {
         const [something] = React.useState(null);
diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
index fe2e713d8a3ba..04aaf0c2ac706 100644
--- a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
+++ b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
@@ -3080,7 +3080,7 @@ function pushTitle(
         console.error(
           'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an Array with length %s instead.' +
             ' Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert `children` of <title> tags to a single string value' +
-            ' which is why Arrays of length greater than 1 are not supported. When using JSX it can be commong to combine text nodes and value nodes.' +
+            ' which is why Arrays of length greater than 1 are not supported. When using JSX it can be common to combine text nodes and value nodes.' +
             ' For example: <title>hello {nameOfUser}</title>. While not immediately apparent, `children` in this case is an Array with length 2. If your `children` prop' +
             ' is using this form try rewriting it using a template string: <title>{`hello ${nameOfUser}`}</title>.',
           children.length,
@@ -3886,18 +3886,6 @@ const clientRenderedSuspenseBoundaryError1D =
 const clientRenderedSuspenseBoundaryError2 =
   stringToPrecomputedChunk('></template>');
 
-export function pushStartCompletedSuspenseBoundary(
-  target: Array<Chunk | PrecomputedChunk>,
-) {
-  target.push(startCompletedSuspenseBoundary);
-}
-
-export function pushEndCompletedSuspenseBoundary(
-  target: Array<Chunk | PrecomputedChunk>,
-) {
-  target.push(endSuspenseBoundary);
-}
-
 export function writeStartCompletedSuspenseBoundary(
   destination: Destination,
   renderState: RenderState,
diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js
index 725ee666f52af..e4cd9ca93d99e 100644
--- a/packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js
+++ b/packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js
@@ -142,8 +142,6 @@ export {
   makeId,
   pushStartInstance,
   pushEndInstance,
-  pushStartCompletedSuspenseBoundary,
-  pushEndCompletedSuspenseBoundary,
   pushFormStateMarkerIsMatching,
   pushFormStateMarkerIsNotMatching,
   writeStartSegment,
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index 9c91be1225015..777f067a183e8 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -2211,151 +2211,6 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual(<div>Hello</div>);
   });
 
-  // @gate enableSuspenseAvoidThisFallbackFizz
-  it('should respect unstable_avoidThisFallback', async () => {
-    const resolved = {
-      0: false,
-      1: false,
-    };
-    const promiseRes = {};
-    const promises = {
-      0: new Promise(res => {
-        promiseRes[0] = () => {
-          resolved[0] = true;
-          res();
-        };
-      }),
-      1: new Promise(res => {
-        promiseRes[1] = () => {
-          resolved[1] = true;
-          res();
-        };
-      }),
-    };
-
-    const InnerComponent = ({isClient, depth}) => {
-      if (isClient) {
-        // Resuspend after re-rendering on client to check that fallback shows on client
-        throw new Promise(() => {});
-      }
-      if (!resolved[depth]) {
-        throw promises[depth];
-      }
-      return (
-        <div>
-          <Text text={`resolved ${depth}`} />
-        </div>
-      );
-    };
-
-    function App({isClient}) {
-      return (
-        <div>
-          <Text text="Non Suspense Content" />
-          <Suspense
-            fallback={
-              <span>
-                <Text text="Avoided Fallback" />
-              </span>
-            }
-            unstable_avoidThisFallback={true}>
-            <InnerComponent isClient={isClient} depth={0} />
-            <div>
-              <Suspense fallback={<Text text="Fallback" />}>
-                <Suspense
-                  fallback={
-                    <span>
-                      <Text text="Avoided Fallback2" />
-                    </span>
-                  }
-                  unstable_avoidThisFallback={true}>
-                  <InnerComponent isClient={isClient} depth={1} />
-                </Suspense>
-              </Suspense>
-            </div>
-          </Suspense>
-        </div>
-      );
-    }
-
-    await jest.runAllTimers();
-
-    await act(() => {
-      const {pipe} = renderToPipeableStream(<App isClient={false} />);
-      pipe(writable);
-    });
-
-    // Nothing is output since root has a suspense with avoidedThisFallback that hasn't resolved
-    expect(getVisibleChildren(container)).toEqual(undefined);
-    expect(container.innerHTML).not.toContain('Avoided Fallback');
-
-    // resolve first suspense component with avoidThisFallback
-    await act(() => {
-      promiseRes[0]();
-    });
-
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div>resolved 0</div>
-        <div>Fallback</div>
-      </div>,
-    );
-
-    expect(container.innerHTML).not.toContain('Avoided Fallback2');
-
-    await act(() => {
-      promiseRes[1]();
-    });
-
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div>resolved 0</div>
-        <div>
-          <div>resolved 1</div>
-        </div>
-      </div>,
-    );
-
-    let root;
-    await act(async () => {
-      root = ReactDOMClient.hydrateRoot(container, <App isClient={false} />);
-      await waitForAll([]);
-      await jest.runAllTimers();
-    });
-
-    // No change after hydration
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div>resolved 0</div>
-        <div>
-          <div>resolved 1</div>
-        </div>
-      </div>,
-    );
-
-    await act(async () => {
-      // Trigger update by changing isClient to true
-      root.render(<App isClient={true} />);
-      await waitForAll([]);
-      await jest.runAllTimers();
-    });
-
-    // Now that we've resuspended at the root we show the root fallback
-    expect(getVisibleChildren(container)).toEqual(
-      <div>
-        Non Suspense Content
-        <div style="display: none;">resolved 0</div>
-        <div style="display: none;">
-          <div>resolved 1</div>
-        </div>
-        <span>Avoided Fallback</span>
-      </div>,
-    );
-  });
-
   it('calls getServerSnapshot instead of getSnapshot', async () => {
     const ref = React.createRef();
 
@@ -5928,7 +5783,7 @@ describe('ReactDOMFizzServer', () => {
           pipe(writable);
         });
       }).toErrorDev([
-        'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an Array with length 2 instead. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert `children` of <title> tags to a single string value which is why Arrays of length greater than 1 are not supported. When using JSX it can be commong to combine text nodes and value nodes. For example: <title>hello {nameOfUser}</title>. While not immediately apparent, `children` in this case is an Array with length 2. If your `children` prop is using this form try rewriting it using a template string: <title>{`hello ${nameOfUser}`}</title>.',
+        'React expects the `children` prop of <title> tags to be a string, number, bigint, or object with a novel `toString` method but found an Array with length 2 instead. Browsers treat all child Nodes of <title> tags as Text content and React expects to be able to convert `children` of <title> tags to a single string value which is why Arrays of length greater than 1 are not supported. When using JSX it can be common to combine text nodes and value nodes. For example: <title>hello {nameOfUser}</title>. While not immediately apparent, `children` in this case is an Array with length 2. If your `children` prop is using this form try rewriting it using a template string: <title>{`hello ${nameOfUser}`}</title>.',
       ]);
 
       expect(getVisibleChildren(document.head)).toEqual(<title />);
diff --git a/packages/react-markup/src/ReactFizzConfigMarkup.js b/packages/react-markup/src/ReactFizzConfigMarkup.js
index 6b43d0bad39a7..048e54933930d 100644
--- a/packages/react-markup/src/ReactFizzConfigMarkup.js
+++ b/packages/react-markup/src/ReactFizzConfigMarkup.js
@@ -49,8 +49,6 @@ export {
   getChildFormatContext,
   makeId,
   pushEndInstance,
-  pushStartCompletedSuspenseBoundary,
-  pushEndCompletedSuspenseBoundary,
   pushFormStateMarkerIsMatching,
   pushFormStateMarkerIsNotMatching,
   writeStartSegment,
diff --git a/packages/react-reconciler/src/ReactFiberHooks.js b/packages/react-reconciler/src/ReactFiberHooks.js
index 033e71610f5c6..d2df61063f687 100644
--- a/packages/react-reconciler/src/ReactFiberHooks.js
+++ b/packages/react-reconciler/src/ReactFiberHooks.js
@@ -40,7 +40,6 @@ import {
   enableCache,
   enableLazyContextPropagation,
   enableTransitionTracing,
-  enableUseMemoCacheHook,
   enableUseEffectEventHook,
   enableLegacyCache,
   debugRenderPhaseSideEffectsForStrictMode,
@@ -277,8 +276,7 @@ export type FunctionComponentUpdateQueue = {
   lastEffect: Effect | null,
   events: Array<EventFunctionPayload<any, any, any>> | null,
   stores: Array<StoreConsistencyCheck<any>> | null,
-  // NOTE: optional, only set when enableUseMemoCacheHook is enabled
-  memoCache?: MemoCache | null,
+  memoCache: MemoCache | null,
 };
 
 type BasicStateAction<S> = (S => S) | S;
@@ -1127,25 +1125,12 @@ function unstable_useContextWithBailout<T>(
   return readContextAndCompare(context, select);
 }
 
-// NOTE: defining two versions of this function to avoid size impact when this feature is disabled.
-// Previously this function was inlined, the additional `memoCache` property makes it not inlined.
-let createFunctionComponentUpdateQueue: () => FunctionComponentUpdateQueue;
-if (enableUseMemoCacheHook) {
-  createFunctionComponentUpdateQueue = () => {
-    return {
-      lastEffect: null,
-      events: null,
-      stores: null,
-      memoCache: null,
-    };
-  };
-} else {
-  createFunctionComponentUpdateQueue = () => {
-    return {
-      lastEffect: null,
-      events: null,
-      stores: null,
-    };
+function createFunctionComponentUpdateQueue(): FunctionComponentUpdateQueue {
+  return {
+    lastEffect: null,
+    events: null,
+    stores: null,
+    memoCache: null,
   };
 }
 
@@ -1155,13 +1140,11 @@ function resetFunctionComponentUpdateQueue(
   updateQueue.lastEffect = null;
   updateQueue.events = null;
   updateQueue.stores = null;
-  if (enableUseMemoCacheHook) {
-    if (updateQueue.memoCache != null) {
-      // NOTE: this function intentionally does not reset memoCache data. We reuse updateQueue for the memo
-      // cache to avoid increasing the size of fibers that don't need a cache, but we don't want to reset
-      // the cache when other properties are reset.
-      updateQueue.memoCache.index = 0;
-    }
+  if (updateQueue.memoCache != null) {
+    // NOTE: this function intentionally does not reset memoCache data. We reuse updateQueue for the memo
+    // cache to avoid increasing the size of fibers that don't need a cache, but we don't want to reset
+    // the cache when other properties are reset.
+    updateQueue.memoCache.index = 0;
   }
 }
 
@@ -3982,13 +3965,11 @@ export const ContextOnlyDispatcher: Dispatcher = {
   useFormState: throwInvalidHookError,
   useActionState: throwInvalidHookError,
   useOptimistic: throwInvalidHookError,
+  useMemoCache: throwInvalidHookError,
 };
 if (enableCache) {
   (ContextOnlyDispatcher: Dispatcher).useCacheRefresh = throwInvalidHookError;
 }
-if (enableUseMemoCacheHook) {
-  (ContextOnlyDispatcher: Dispatcher).useMemoCache = throwInvalidHookError;
-}
 if (enableUseEffectEventHook) {
   (ContextOnlyDispatcher: Dispatcher).useEffectEvent = throwInvalidHookError;
 }
@@ -4023,13 +4004,11 @@ const HooksDispatcherOnMount: Dispatcher = {
   useFormState: mountActionState,
   useActionState: mountActionState,
   useOptimistic: mountOptimistic,
+  useMemoCache,
 };
 if (enableCache) {
   (HooksDispatcherOnMount: Dispatcher).useCacheRefresh = mountRefresh;
 }
-if (enableUseMemoCacheHook) {
-  (HooksDispatcherOnMount: Dispatcher).useMemoCache = useMemoCache;
-}
 if (enableUseEffectEventHook) {
   (HooksDispatcherOnMount: Dispatcher).useEffectEvent = mountEvent;
 }
@@ -4064,13 +4043,11 @@ const HooksDispatcherOnUpdate: Dispatcher = {
   useFormState: updateActionState,
   useActionState: updateActionState,
   useOptimistic: updateOptimistic,
+  useMemoCache,
 };
 if (enableCache) {
   (HooksDispatcherOnUpdate: Dispatcher).useCacheRefresh = updateRefresh;
 }
-if (enableUseMemoCacheHook) {
-  (HooksDispatcherOnUpdate: Dispatcher).useMemoCache = useMemoCache;
-}
 if (enableUseEffectEventHook) {
   (HooksDispatcherOnUpdate: Dispatcher).useEffectEvent = updateEvent;
 }
@@ -4106,13 +4083,11 @@ const HooksDispatcherOnRerender: Dispatcher = {
   useFormState: rerenderActionState,
   useActionState: rerenderActionState,
   useOptimistic: rerenderOptimistic,
+  useMemoCache,
 };
 if (enableCache) {
   (HooksDispatcherOnRerender: Dispatcher).useCacheRefresh = updateRefresh;
 }
-if (enableUseMemoCacheHook) {
-  (HooksDispatcherOnRerender: Dispatcher).useMemoCache = useMemoCache;
-}
 if (enableUseEffectEventHook) {
   (HooksDispatcherOnRerender: Dispatcher).useEffectEvent = updateEvent;
 }
@@ -4307,6 +4282,7 @@ if (__DEV__) {
       return mountOptimistic(passthrough, reducer);
     },
     useHostTransitionStatus,
+    useMemoCache,
   };
   if (enableCache) {
     (HooksDispatcherOnMountInDEV: Dispatcher).useCacheRefresh =
@@ -4316,9 +4292,6 @@ if (__DEV__) {
         return mountRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (HooksDispatcherOnMountInDEV: Dispatcher).useMemoCache = useMemoCache;
-  }
   if (enableUseEffectEventHook) {
     (HooksDispatcherOnMountInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
@@ -4511,6 +4484,7 @@ if (__DEV__) {
       return mountOptimistic(passthrough, reducer);
     },
     useHostTransitionStatus,
+    useMemoCache,
   };
   if (enableCache) {
     (HooksDispatcherOnMountWithHookTypesInDEV: Dispatcher).useCacheRefresh =
@@ -4520,10 +4494,6 @@ if (__DEV__) {
         return mountRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (HooksDispatcherOnMountWithHookTypesInDEV: Dispatcher).useMemoCache =
-      useMemoCache;
-  }
   if (enableUseEffectEventHook) {
     (HooksDispatcherOnMountWithHookTypesInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
@@ -4715,6 +4685,7 @@ if (__DEV__) {
       return updateOptimistic(passthrough, reducer);
     },
     useHostTransitionStatus,
+    useMemoCache,
   };
   if (enableCache) {
     (HooksDispatcherOnUpdateInDEV: Dispatcher).useCacheRefresh =
@@ -4724,9 +4695,6 @@ if (__DEV__) {
         return updateRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (HooksDispatcherOnUpdateInDEV: Dispatcher).useMemoCache = useMemoCache;
-  }
   if (enableUseEffectEventHook) {
     (HooksDispatcherOnUpdateInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
@@ -4918,6 +4886,7 @@ if (__DEV__) {
       return rerenderOptimistic(passthrough, reducer);
     },
     useHostTransitionStatus,
+    useMemoCache,
   };
   if (enableCache) {
     (HooksDispatcherOnRerenderInDEV: Dispatcher).useCacheRefresh =
@@ -4927,9 +4896,6 @@ if (__DEV__) {
         return updateRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (HooksDispatcherOnRerenderInDEV: Dispatcher).useMemoCache = useMemoCache;
-  }
   if (enableUseEffectEventHook) {
     (HooksDispatcherOnRerenderInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
@@ -5141,6 +5107,10 @@ if (__DEV__) {
       mountHookTypesDev();
       return mountOptimistic(passthrough, reducer);
     },
+    useMemoCache(size: number): Array<any> {
+      warnInvalidHookAccess();
+      return useMemoCache(size);
+    },
     useHostTransitionStatus,
   };
   if (enableCache) {
@@ -5151,13 +5121,6 @@ if (__DEV__) {
         return mountRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (InvalidNestedHooksDispatcherOnMountInDEV: Dispatcher).useMemoCache =
-      function (size: number): Array<any> {
-        warnInvalidHookAccess();
-        return useMemoCache(size);
-      };
-  }
   if (enableUseEffectEventHook) {
     (InvalidNestedHooksDispatcherOnMountInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
@@ -5372,6 +5335,10 @@ if (__DEV__) {
       updateHookTypesDev();
       return updateOptimistic(passthrough, reducer);
     },
+    useMemoCache(size: number): Array<any> {
+      warnInvalidHookAccess();
+      return useMemoCache(size);
+    },
     useHostTransitionStatus,
   };
   if (enableCache) {
@@ -5382,13 +5349,6 @@ if (__DEV__) {
         return updateRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (InvalidNestedHooksDispatcherOnUpdateInDEV: Dispatcher).useMemoCache =
-      function (size: number): Array<any> {
-        warnInvalidHookAccess();
-        return useMemoCache(size);
-      };
-  }
   if (enableUseEffectEventHook) {
     (InvalidNestedHooksDispatcherOnUpdateInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
@@ -5603,6 +5563,10 @@ if (__DEV__) {
       updateHookTypesDev();
       return rerenderOptimistic(passthrough, reducer);
     },
+    useMemoCache(size: number): Array<any> {
+      warnInvalidHookAccess();
+      return useMemoCache(size);
+    },
     useHostTransitionStatus,
   };
   if (enableCache) {
@@ -5613,13 +5577,6 @@ if (__DEV__) {
         return updateRefresh();
       };
   }
-  if (enableUseMemoCacheHook) {
-    (InvalidNestedHooksDispatcherOnRerenderInDEV: Dispatcher).useMemoCache =
-      function (size: number): Array<any> {
-        warnInvalidHookAccess();
-        return useMemoCache(size);
-      };
-  }
   if (enableUseEffectEventHook) {
     (InvalidNestedHooksDispatcherOnRerenderInDEV: Dispatcher).useEffectEvent =
       function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
diff --git a/packages/react-reconciler/src/__tests__/useMemoCache-test.js b/packages/react-reconciler/src/__tests__/useMemoCache-test.js
index 520cd7cb72463..c07d3a6d9960c 100644
--- a/packages/react-reconciler/src/__tests__/useMemoCache-test.js
+++ b/packages/react-reconciler/src/__tests__/useMemoCache-test.js
@@ -58,7 +58,6 @@ describe('useMemoCache()', () => {
     ErrorBoundary = _ErrorBoundary;
   });
 
-  // @gate enableUseMemoCacheHook
   it('render component using cache', async () => {
     function Component(props) {
       const cache = useMemoCache(1);
@@ -75,7 +74,6 @@ describe('useMemoCache()', () => {
     expect(root).toMatchRenderedOutput('Ok');
   });
 
-  // @gate enableUseMemoCacheHook
   it('update component using cache', async () => {
     let setX;
     let forceUpdate;
@@ -145,7 +143,6 @@ describe('useMemoCache()', () => {
     expect(data).toBe(data1); // confirm that the cache persisted across renders
   });
 
-  // @gate enableUseMemoCacheHook
   it('update component using cache with setstate during render', async () => {
     let setN;
     function Component(props) {
@@ -210,7 +207,6 @@ describe('useMemoCache()', () => {
     expect(data).toBe(data0);
   });
 
-  // @gate enableUseMemoCacheHook
   it('update component using cache with throw during render', async () => {
     let setN;
     let shouldFail = true;
@@ -293,7 +289,6 @@ describe('useMemoCache()', () => {
     expect(data).toBe(data1); // confirm that the cache persisted across renders
   });
 
-  // @gate enableUseMemoCacheHook
   it('update component and custom hook with caches', async () => {
     let setX;
     let forceUpdate;
@@ -370,7 +365,6 @@ describe('useMemoCache()', () => {
     expect(data).toBe(data1); // confirm that the cache persisted across renders
   });
 
-  // @gate enableUseMemoCacheHook
   it('reuses computations from suspended/interrupted render attempts during an update', async () => {
     // This test demonstrates the benefit of a shared memo cache. By "shared" I
     // mean multiple concurrent render attempts of the same component/hook use
@@ -624,7 +618,6 @@ describe('useMemoCache()', () => {
     );
   });
 
-  // @gate enableUseMemoCacheHook
   it('(repro) infinite renders when used with setState during render', async () => {
     // Output of react compiler on `useUserMemo`
     function useCompilerMemo(value) {
diff --git a/packages/react-server/src/ReactFizzHooks.js b/packages/react-server/src/ReactFizzHooks.js
index e4e81af8fabb8..a163aa11516b7 100644
--- a/packages/react-server/src/ReactFizzHooks.js
+++ b/packages/react-server/src/ReactFizzHooks.js
@@ -41,7 +41,6 @@ import {createFastHash} from './ReactServerStreamConfig';
 import {
   enableCache,
   enableUseEffectEventHook,
-  enableUseMemoCacheHook,
   enableUseResourceEffectHook,
 } from 'shared/ReactFeatureFlags';
 import is from 'shared/objectIs';
@@ -859,6 +858,7 @@ export const HooksDispatcher: Dispatcher = supportsClientAPIs
       useActionState,
       useFormState: useActionState,
       useHostTransitionStatus,
+      useMemoCache,
     };
 
 if (enableCache) {
@@ -867,9 +867,6 @@ if (enableCache) {
 if (enableUseEffectEventHook) {
   HooksDispatcher.useEffectEvent = useEffectEvent;
 }
-if (enableUseMemoCacheHook) {
-  HooksDispatcher.useMemoCache = useMemoCache;
-}
 if (enableUseResourceEffectHook) {
   HooksDispatcher.useResourceEffect = supportsClientAPIs
     ? noop
diff --git a/packages/react-server/src/ReactFizzServer.js b/packages/react-server/src/ReactFizzServer.js
index f245861ba0012..ad6721ec60796 100644
--- a/packages/react-server/src/ReactFizzServer.js
+++ b/packages/react-server/src/ReactFizzServer.js
@@ -65,8 +65,6 @@ import {
   pushTextInstance,
   pushStartInstance,
   pushEndInstance,
-  pushStartCompletedSuspenseBoundary,
-  pushEndCompletedSuspenseBoundary,
   pushSegmentFinale,
   getChildFormatContext,
   writeHoistables,
@@ -155,7 +153,6 @@ import {
   disableLegacyContext,
   disableLegacyContextForFunctionComponents,
   enableScopeAPI,
-  enableSuspenseAvoidThisFallbackFizz,
   enableCache,
   enablePostpone,
   enableHalt,
@@ -1490,28 +1487,6 @@ function replaySuspenseBoundary(
   request.pingedTasks.push(suspendedFallbackTask);
 }
 
-function renderBackupSuspenseBoundary(
-  request: Request,
-  task: Task,
-  keyPath: KeyNode,
-  props: Object,
-) {
-  const content = props.children;
-  const segment = task.blockedSegment;
-  const prevKeyPath = task.keyPath;
-  task.keyPath = keyPath;
-  if (segment === null) {
-    // Replay
-    renderNode(request, task, content, -1);
-  } else {
-    // Render
-    pushStartCompletedSuspenseBoundary(segment.chunks);
-    renderNode(request, task, content, -1);
-    pushEndCompletedSuspenseBoundary(segment.chunks);
-  }
-  task.keyPath = prevKeyPath;
-}
-
 function renderHostElement(
   request: Request,
   task: Task,
@@ -2194,14 +2169,7 @@ function renderElement(
       throw new Error('ReactDOMServer does not yet support scope components.');
     }
     case REACT_SUSPENSE_TYPE: {
-      if (
-        enableSuspenseAvoidThisFallbackFizz &&
-        props.unstable_avoidThisFallback === true
-      ) {
-        renderBackupSuspenseBoundary(request, task, keyPath, props);
-      } else {
-        renderSuspenseBoundary(request, task, keyPath, props);
-      }
+      renderSuspenseBoundary(request, task, keyPath, props);
       return;
     }
   }
diff --git a/packages/react-server/src/forks/ReactFizzConfig.custom.js b/packages/react-server/src/forks/ReactFizzConfig.custom.js
index 02ce1e4e2afee..be14f349aa286 100644
--- a/packages/react-server/src/forks/ReactFizzConfig.custom.js
+++ b/packages/react-server/src/forks/ReactFizzConfig.custom.js
@@ -51,10 +51,6 @@ export const makeId = $$$config.makeId;
 export const pushTextInstance = $$$config.pushTextInstance;
 export const pushStartInstance = $$$config.pushStartInstance;
 export const pushEndInstance = $$$config.pushEndInstance;
-export const pushStartCompletedSuspenseBoundary =
-  $$$config.pushStartCompletedSuspenseBoundary;
-export const pushEndCompletedSuspenseBoundary =
-  $$$config.pushEndCompletedSuspenseBoundary;
 export const pushSegmentFinale = $$$config.pushSegmentFinale;
 export const pushFormStateMarkerIsMatching =
   $$$config.pushFormStateMarkerIsMatching;
diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
index 8ac0fd86e28ed..f28d123e61e5b 100644
--- a/packages/shared/ReactFeatureFlags.js
+++ b/packages/shared/ReactFeatureFlags.js
@@ -108,16 +108,11 @@ export const enableLegacyHidden = false;
 
 // Enables unstable_avoidThisFallback feature in Fiber
 export const enableSuspenseAvoidThisFallback = false;
-// Enables unstable_avoidThisFallback feature in Fizz
-export const enableSuspenseAvoidThisFallbackFizz = false;
 
 export const enableCPUSuspense = __EXPERIMENTAL__;
 
 export const enableHydrationLaneScheduling = true;
 
-// Enables useMemoCache hook, intended as a compilation target for
-// auto-memoization.
-export const enableUseMemoCacheHook = true;
 // Test this at Meta before enabling.
 export const enableNoCloningMemoCache = false;
 
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb.js b/packages/shared/forks/ReactFeatureFlags.native-fb.js
index 1948a38163cca..4d89fa091061a 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb.js
@@ -73,14 +73,12 @@ export const enableComponentPerformanceTrack = false;
 export const enableScopeAPI = false;
 export const enableServerComponentLogs = true;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableSuspenseCallback = true;
 export const enableTaint = true;
 export const enableTransitionTracing = false;
 export const enableTrustedTypesIntegration = false;
 export const enableUpdaterTracking = __PROFILE__;
 export const enableUseEffectEventHook = false;
-export const enableUseMemoCacheHook = true;
 export const favorSafetyOverHydrationPerf = true;
 export const renameElementSymbol = false;
 export const retryLaneExpirationMs = 5000;
diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
index 12d1598e6a16e..0407f01910b75 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-oss.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -63,13 +63,11 @@ export const enableScopeAPI = false;
 export const enableServerComponentLogs = true;
 export const enableShallowPropDiffing = false;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableSuspenseCallback = false;
 export const enableTaint = true;
 export const enableTransitionTracing = false;
 export const enableTrustedTypesIntegration = false;
 export const enableUseEffectEventHook = false;
-export const enableUseMemoCacheHook = true;
 export const favorSafetyOverHydrationPerf = true;
 export const passChildrenWhenCloningPersistedNodes = false;
 export const renameElementSymbol = true;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
index 609c5628063b9..b83cb9a99fc3d 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
@@ -33,9 +33,7 @@ export const enableSuspenseCallback = false;
 export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
-export const enableUseMemoCacheHook = true;
 export const enableNoCloningMemoCache = false;
 export const enableUseEffectEventHook = false;
 export const favorSafetyOverHydrationPerf = true;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
index 169c5c9e2878b..115117685aeb4 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
@@ -57,14 +57,12 @@ export const enableScopeAPI = false;
 export const enableServerComponentLogs = true;
 export const enableShallowPropDiffing = false;
 export const enableSuspenseAvoidThisFallback = false;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableSuspenseCallback = false;
 export const enableTaint = true;
 export const enableTransitionTracing = false;
 export const enableTrustedTypesIntegration = false;
 export const enableUpdaterTracking = false;
 export const enableUseEffectEventHook = false;
-export const enableUseMemoCacheHook = true;
 export const favorSafetyOverHydrationPerf = true;
 export const passChildrenWhenCloningPersistedNodes = false;
 export const renameElementSymbol = false;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
index 6ecd34dfbd1bd..cad15eecc8c11 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
@@ -35,9 +35,7 @@ export const disableLegacyContextForFunctionComponents = false;
 export const enableTrustedTypesIntegration = false;
 export const disableTextareaChildren = false;
 export const enableSuspenseAvoidThisFallback = true;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 export const enableCPUSuspense = false;
-export const enableUseMemoCacheHook = true;
 export const enableNoCloningMemoCache = false;
 export const enableUseEffectEventHook = false;
 export const favorSafetyOverHydrationPerf = true;
diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
index be91e1c8e4ecd..eea2ba4230f50 100644
--- a/packages/shared/forks/ReactFeatureFlags.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -51,10 +51,8 @@ export const enableUpdaterTracking = __PROFILE__;
 export const enableFabricCompleteRootInCommitPhase = false;
 
 export const enableSuspenseAvoidThisFallback = true;
-export const enableSuspenseAvoidThisFallbackFizz = false;
 
 export const enableCPUSuspense = true;
-export const enableUseMemoCacheHook = true;
 export const enableUseEffectEventHook = true;
 export const enableMoveBefore = false;
 export const disableInputAttributeSyncing = false;