diff --git a/common/boot_control_interface.h b/common/boot_control_interface.h
index 43517ce..392d785 100644
--- a/common/boot_control_interface.h
+++ b/common/boot_control_interface.h
@@ -66,7 +66,9 @@
   // Determines the block device for the given partition name and slot number.
   // The |slot| number must be between 0 and GetNumSlots() - 1 and the
   // |partition_name| is a platform-specific name that identifies a partition on
-  // every slot. On success, returns true and stores the block device in
+  // every slot. In order to access the dynamic partitions in the target slot,
+  // InitPartitionMetadata() must be called (once per payload) prior to calling
+  // this function. On success, returns true and stores the block device in
   // |device|.
   virtual bool GetPartitionDevice(const std::string& partition_name,
                                   Slot slot,
@@ -92,14 +94,14 @@
   // of the operation.
   virtual bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) = 0;
 
-  // Initialize metadata of underlying partitions for a given |slot|.
-  // Ensure that all updateable groups with the suffix GetSuffix(|slot|) exactly
-  // matches the layout specified in |partition_metadata|. Ensure that
-  // partitions at the specified |slot| has a given size and updateable group,
-  // as specified by |partition_metadata|. Sizes must be aligned to the logical
-  // block size of the super partition.
+  // Initializes the metadata of the underlying partitions for a given |slot|
+  // and sets up the states for accessing dynamic partitions.
+  // |partition_metadata| will be written to the specified |slot| if
+  // |update_metadata| is set.
   virtual bool InitPartitionMetadata(
-      Slot slot, const PartitionMetadata& partition_metadata) = 0;
+      Slot slot,
+      const PartitionMetadata& partition_metadata,
+      bool update_metadata) = 0;
 
   // Do necessary clean-up operations after the whole update.
   virtual void Cleanup() = 0;
diff --git a/common/boot_control_stub.cc b/common/boot_control_stub.cc
index ca880d4..0fe8a98 100644
--- a/common/boot_control_stub.cc
+++ b/common/boot_control_stub.cc
@@ -60,7 +60,9 @@
 }
 
 bool BootControlStub::InitPartitionMetadata(
-    Slot slot, const PartitionMetadata& partition_metadata) {
+    Slot slot,
+    const PartitionMetadata& partition_metadata,
+    bool update_metadata) {
   LOG(ERROR) << __FUNCTION__ << " should never be called.";
   return false;
 }
diff --git a/common/boot_control_stub.h b/common/boot_control_stub.h
index 0950997..8dfaffc 100644
--- a/common/boot_control_stub.h
+++ b/common/boot_control_stub.h
@@ -45,8 +45,9 @@
   bool MarkSlotUnbootable(BootControlInterface::Slot slot) override;
   bool SetActiveBootSlot(BootControlInterface::Slot slot) override;
   bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) override;
-  bool InitPartitionMetadata(
-      Slot slot, const PartitionMetadata& partition_metadata) override;
+  bool InitPartitionMetadata(Slot slot,
+                             const PartitionMetadata& partition_metadata,
+                             bool update_metadata) override;
   void Cleanup() override;
 
  private:
diff --git a/common/constants.cc b/common/constants.cc
index 3ae7a60..310f1b2 100644
--- a/common/constants.cc
+++ b/common/constants.cc
@@ -37,8 +37,8 @@
 const char kPrefsDailyMetricsLastReportedAt[] =
     "daily-metrics-last-reported-at";
 const char kPrefsDeltaUpdateFailures[] = "delta-update-failures";
-const char kPrefsDynamicPartitionMetadataInitialized[] =
-    "dynamic-partition-metadata-initialized";
+const char kPrefsDynamicPartitionMetadataUpdated[] =
+    "dynamic-partition-metadata-updated";
 const char kPrefsFullPayloadAttemptNumber[] = "full-payload-attempt-number";
 const char kPrefsInstallDateDays[] = "install-date-days";
 const char kPrefsLastActivePingDay[] = "last-active-ping-day";
diff --git a/common/constants.h b/common/constants.h
index 61e5ddd..d5a8ae3 100644
--- a/common/constants.h
+++ b/common/constants.h
@@ -41,7 +41,7 @@
 extern const char kPrefsCurrentUrlIndex[];
 extern const char kPrefsDailyMetricsLastReportedAt[];
 extern const char kPrefsDeltaUpdateFailures[];
-extern const char kPrefsDynamicPartitionMetadataInitialized[];
+extern const char kPrefsDynamicPartitionMetadataUpdated[];
 extern const char kPrefsFullPayloadAttemptNumber[];
 extern const char kPrefsInstallDateDays[];
 extern const char kPrefsLastActivePingDay[];
diff --git a/common/fake_boot_control.h b/common/fake_boot_control.h
index 513c149..ba975a2 100644
--- a/common/fake_boot_control.h
+++ b/common/fake_boot_control.h
@@ -74,8 +74,9 @@
     return true;
   }
 
-  bool InitPartitionMetadata(
-      Slot slot, const PartitionMetadata& partition_metadata) override {
+  bool InitPartitionMetadata(Slot slot,
+                             const PartitionMetadata& partition_metadata,
+                             bool update_metadata) override {
     return true;
   }