diff --git a/.hgtags b/.hgtags
index 77872b782499..f98eac6c7979 100644
--- a/.hgtags
+++ b/.hgtags
@@ -57,3 +57,4 @@ dba2abb7db57078c5a4810884834d3056a5d56c2 last-mozilla-central
 138f593553b66c9f815e8f57870c19d6347f7702 UPDATE_PACKAGING_R11_1_MU
 e56ecd8b3a68c158025207c5fd081d043e28f5ce GECKO_2_0_BASE
 fca718600ca09414177785caa5f937505e1b7c46 FIREFOX_4_0_1_RELEASE
+fca718600ca09414177785caa5f937505e1b7c46 FIREFOX_4_0_1_BUILD1