diff --git a/common/constants.h b/common/constants.h
index d97c5fb..897d2e2 100644
--- a/common/constants.h
+++ b/common/constants.h
@@ -88,6 +88,7 @@
 extern const char kPrefsUpdateStateSHA256Context[];
 extern const char kPrefsUpdateStateSignatureBlob[];
 extern const char kPrefsUpdateStateSignedSHA256Context[];
+extern const char kPrefsUpdateBootTimestampStart[];
 extern const char kPrefsUpdateTimestampStart[];
 extern const char kPrefsUrlSwitchCount[];
 extern const char kPrefsWallClockScatteringWaitPeriod[];