diff --git a/core/build_id.mk b/core/build_id.mk
index 31f7fc1..70bd235 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -1,4 +1,3 @@
-
 #
 # Copyright (C) 2008 The Android Open Source Project
 #
@@ -14,10 +13,20 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+
+#
+# Defines branch-specific values.
+#
+
 # BUILD_ID is usually used to specify the branch name
 # (like "MAIN") or a branch name and a release candidate
-# (like "CRB01").  It must be a single word, and is
+# (like "TC1-RC5").  It must be a single word, and is
 # capitalized by convention.
+#
+BUILD_ID := MR1
 
-export BUILD_ID=IMM68C
-
+# DISPLAY_BUILD_NUMBER should only be set for development branches,
+# If set, the BUILD_NUMBER (cl) is appended to the BUILD_ID for
+# a more descriptive BUILD_ID_DISPLAY, otherwise BUILD_ID_DISPLAY
+# is the same as BUILD_ID
+DISPLAY_BUILD_NUMBER := true