diff --git a/action_processor.h b/action_processor.h
index 0cf6ff6..124fe00 100644
--- a/action_processor.h
+++ b/action_processor.h
@@ -46,6 +46,9 @@
   kActionCodeOmahaRequestNoUpdateCheckStatus = 203,
   kActionCodeOmahaRequestBadUpdateCheckStatus = 204,
   kActionCodeOmahaRequestHTTPResponseBase = 2000,  // + HTTP response code
+
+  // Bit flags.
+  kActionCodeBootModeFlag = 1 << 31,  // Set if boot mode not normal.
 };
 
 class AbstractAction;