diff --git a/fake_boot_control.h b/fake_boot_control.h
index 9d1b54b..f5dcdd6 100644
--- a/fake_boot_control.h
+++ b/fake_boot_control.h
@@ -65,6 +65,8 @@
     return true;
   }
 
+  bool SetActiveBootSlot(Slot slot) override { return true; }
+
   bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) override {
     // We run the callback directly from here to avoid having to setup a message
     // loop in the test environment.