diff --git a/aosp/dynamic_partition_control_android.cc b/aosp/dynamic_partition_control_android.cc
index 825e0d6..6d33a09 100644
--- a/aosp/dynamic_partition_control_android.cc
+++ b/aosp/dynamic_partition_control_android.cc
@@ -1420,7 +1420,7 @@
   return snapshot_->OpenSnapshotWriter(params, std::move(source_path));
 }  // namespace chromeos_update_engine
 
-FileDescriptorPtr DynamicPartitionControlAndroid::OpenCowFd(
+std::unique_ptr<FileDescriptor> DynamicPartitionControlAndroid::OpenCowFd(
     const std::string& unsuffixed_partition_name,
     const std::optional<std::string>& source_path,
     bool is_append) {
@@ -1438,7 +1438,7 @@
     LOG(ERROR) << "ICowWriter::OpenReader() failed.";
     return nullptr;
   }
-  return std::make_shared<CowWriterFileDescriptor>(std::move(cow_writer),
+  return std::make_unique<CowWriterFileDescriptor>(std::move(cow_writer),
                                                    std::move(reader));
 }
 
diff --git a/aosp/dynamic_partition_control_android.h b/aosp/dynamic_partition_control_android.h
index d0842a9..cebca07 100644
--- a/aosp/dynamic_partition_control_android.h
+++ b/aosp/dynamic_partition_control_android.h
@@ -104,9 +104,10 @@
       const std::string& unsuffixed_partition_name,
       const std::optional<std::string>& source_path,
       bool is_append) override;
-  FileDescriptorPtr OpenCowFd(const std::string& unsuffixed_partition_name,
-                              const std::optional<std::string>&,
-                              bool is_append = false) override;
+  std::unique_ptr<FileDescriptor> OpenCowFd(
+      const std::string& unsuffixed_partition_name,
+      const std::optional<std::string>&,
+      bool is_append = false) override;
 
   bool MapAllPartitions() override;
   bool UnmapAllPartitions() override;
diff --git a/aosp/mock_dynamic_partition_control_android.h b/aosp/mock_dynamic_partition_control_android.h
index 428b6c7..33ef39c 100644
--- a/aosp/mock_dynamic_partition_control_android.h
+++ b/aosp/mock_dynamic_partition_control_android.h
@@ -94,7 +94,7 @@
                const std::optional<std::string>& source_path,
                bool is_append),
               (override));
-  MOCK_METHOD(FileDescriptorPtr,
+  MOCK_METHOD(std::unique_ptr<FileDescriptor>,
               OpenCowFd,
               (const std::string& unsuffixed_partition_name,
                const std::optional<std::string>& source_path,