diff --git a/common/dynamic_partition_control_interface.h b/common/dynamic_partition_control_interface.h
index c17bafb..c171fb5 100644
--- a/common/dynamic_partition_control_interface.h
+++ b/common/dynamic_partition_control_interface.h
@@ -69,6 +69,8 @@
                                           const DeltaArchiveManifest& manifest,
                                           bool update) = 0;
 
+  // After writing to new partitions, before rebooting into the new slot, call
+  // this function to indicate writes to new partitions are done.
   virtual bool FinishUpdate() = 0;
 };