diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/HwcBufferCache.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/HwcBufferCache.h
index aa049a8..fd22aa3 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/HwcBufferCache.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/HwcBufferCache.h
@@ -57,11 +57,15 @@
     void getHwcBuffer(int slot, const sp<GraphicBuffer>& buffer, uint32_t* outSlot,
                       sp<GraphicBuffer>* outBuffer);
 
+    // Special caching slot for the layer caching feature.
+    static const constexpr size_t FLATTENER_CACHING_SLOT = BufferQueue::NUM_BUFFER_SLOTS;
+
 private:
     // an array where the index corresponds to a slot and the value corresponds to a (counter,
     // buffer) pair. "counter" is a unique value that indicates the last time this slot was updated
     // or used and allows us to keep track of the least-recently used buffer.
-    wp<GraphicBuffer> mBuffers[BufferQueue::NUM_BUFFER_SLOTS];
+    static const constexpr size_t kMaxLayerBufferCount = BufferQueue::NUM_BUFFER_SLOTS + 1;
+    wp<GraphicBuffer> mBuffers[kMaxLayerBufferCount];
 };
 
 } // namespace compositionengine::impl
diff --git a/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp b/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp
index cedc333..f95382d 100644
--- a/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp
@@ -36,7 +36,7 @@
                                   sp<GraphicBuffer>* outBuffer) {
     // default is 0
     if (slot == BufferQueue::INVALID_BUFFER_SLOT || slot < 0 ||
-        slot >= BufferQueue::NUM_BUFFER_SLOTS) {
+        slot >= static_cast<int32_t>(kMaxLayerBufferCount)) {
         *outSlot = 0;
     } else {
         *outSlot = static_cast<uint32_t>(slot);
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
index 7f5c01c..01da070 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
@@ -18,6 +18,7 @@
 #include <compositionengine/DisplayColorProfile.h>
 #include <compositionengine/LayerFECompositionState.h>
 #include <compositionengine/Output.h>
+#include <compositionengine/impl/HwcBufferCache.h>
 #include <compositionengine/impl/OutputCompositionState.h>
 #include <compositionengine/impl/OutputLayer.h>
 #include <compositionengine/impl/OutputLayerCompositionState.h>
@@ -548,9 +549,11 @@
 
     sp<GraphicBuffer> buffer = outputIndependentState.buffer;
     sp<Fence> acquireFence = outputIndependentState.acquireFence;
+    int slot = outputIndependentState.bufferSlot;
     if (getState().overrideInfo.buffer != nullptr) {
         buffer = getState().overrideInfo.buffer->getBuffer();
         acquireFence = getState().overrideInfo.acquireFence;
+        slot = HwcBufferCache::FLATTENER_CACHING_SLOT;
     }
 
     ALOGV("Writing buffer %p", buffer.get());
@@ -559,8 +562,7 @@
     sp<GraphicBuffer> hwcBuffer;
     // We need access to the output-dependent state for the buffer cache there,
     // though otherwise the buffer is not output-dependent.
-    editState().hwc->hwcBufferCache.getHwcBuffer(outputIndependentState.bufferSlot, buffer,
-                                                 &hwcSlot, &hwcBuffer);
+    editState().hwc->hwcBufferCache.getHwcBuffer(slot, buffer, &hwcSlot, &hwcBuffer);
 
     if (auto error = hwcLayer->setBuffer(hwcSlot, hwcBuffer, acquireFence);
         error != hal::Error::NONE) {
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
index e876a61..3adfe40 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <compositionengine/impl/HwcBufferCache.h>
 #include <compositionengine/impl/OutputLayer.h>
 #include <compositionengine/impl/OutputLayerCompositionState.h>
 #include <compositionengine/mock/CompositionEngine.h>
@@ -702,6 +703,7 @@
     static constexpr ui::Dataspace kOverrideDataspace = static_cast<ui::Dataspace>(72);
     static constexpr int kSupportedPerFrameMetadata = 101;
     static constexpr int kExpectedHwcSlot = 0;
+    static constexpr int kOverrideHwcSlot = impl::HwcBufferCache::FLATTENER_CACHING_SLOT;
     static constexpr bool kLayerGenericMetadata1Mandatory = true;
     static constexpr bool kLayerGenericMetadata2Mandatory = true;
 
@@ -824,10 +826,11 @@
         EXPECT_CALL(*mHwcLayer, setSidebandStream(kSidebandStreamHandle));
     }
 
-    void expectSetHdrMetadataAndBufferCalls(sp<GraphicBuffer> buffer = kBuffer,
+    void expectSetHdrMetadataAndBufferCalls(uint32_t hwcSlot = kExpectedHwcSlot,
+                                            sp<GraphicBuffer> buffer = kBuffer,
                                             sp<Fence> fence = kFence) {
         EXPECT_CALL(*mHwcLayer, setPerFrameMetadata(kSupportedPerFrameMetadata, kHdrMetadata));
-        EXPECT_CALL(*mHwcLayer, setBuffer(kExpectedHwcSlot, buffer, fence));
+        EXPECT_CALL(*mHwcLayer, setBuffer(hwcSlot, buffer, fence));
     }
 
     void expectGenericLayerMetadataCalls() {
@@ -1060,7 +1063,7 @@
                               kOverrideBlendMode, kOverrideAlpha);
     expectPerFrameCommonCalls(SimulateUnsupported::None, kOverrideDataspace, kOverrideVisibleRegion,
                               kOverrideSurfaceDamage);
-    expectSetHdrMetadataAndBufferCalls(kOverrideBuffer, kOverrideFence);
+    expectSetHdrMetadataAndBufferCalls(kOverrideHwcSlot, kOverrideBuffer, kOverrideFence);
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::DEVICE);
     EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));