diff --git a/payload_consumer/filesystem_verifier_action.cc b/payload_consumer/filesystem_verifier_action.cc
index aa2fbaa..4efbe41 100644
--- a/payload_consumer/filesystem_verifier_action.cc
+++ b/payload_consumer/filesystem_verifier_action.cc
@@ -129,8 +129,8 @@
   const InstallPlan::Partition& partition =
       install_plan_.partitions[partition_index_];
 
-  read_fd_ = dynamic_control_->OpenCowReader(
-      partition.name, partition.source_path, true);
+  read_fd_ =
+      dynamic_control_->OpenCowFd(partition.name, partition.source_path, true);
   if (!read_fd_) {
     LOG(ERROR) << "OpenCowReader(" << partition.name << ", "
                << partition.source_path << ") failed.";
diff --git a/payload_consumer/filesystem_verifier_action_unittest.cc b/payload_consumer/filesystem_verifier_action_unittest.cc
index 7d3ee9e..60e36cc 100644
--- a/payload_consumer/filesystem_verifier_action_unittest.cc
+++ b/payload_consumer/filesystem_verifier_action_unittest.cc
@@ -423,14 +423,13 @@
       .WillByDefault(Return(FeatureFlag(FeatureFlag::Value::LAUNCH)));
   ON_CALL(dynamic_control, UpdateUsesSnapshotCompression())
       .WillByDefault(Return(true));
-  ON_CALL(dynamic_control, OpenCowReader(_, _, _))
-      .WillByDefault(Return(fake_fd));
+  ON_CALL(dynamic_control, OpenCowFd(_, _, _)).WillByDefault(Return(fake_fd));
   ON_CALL(dynamic_control, IsDynamicPartition(part.name, _))
       .WillByDefault(Return(true));
 
   EXPECT_CALL(dynamic_control, UpdateUsesSnapshotCompression())
       .Times(AtLeast(1));
-  EXPECT_CALL(dynamic_control, OpenCowReader(part.name, {part.source_path}, _))
+  EXPECT_CALL(dynamic_control, OpenCowFd(part.name, {part.source_path}, _))
       .Times(1);
   EXPECT_CALL(dynamic_control, ListDynamicPartitionsForSlot(_, _, _))
       .WillRepeatedly(