--- a/mobile/android/config/mozconfigs/common
+++ b/mobile/android/config/mozconfigs/common
@@ -3,17 +3,20 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 # This file is included at the top of all native android mozconfigs
 if [ "x$IS_NIGHTLY" = "xyes" ]; then
   MOZ_AUTOMATION_UPLOAD_SYMBOLS=${MOZ_AUTOMATION_UPLOAD_SYMBOLS-1}
 fi
 
 if [ -z "$NO_NDK" ]; then
-  . "$topsrcdir/build/mozconfig.stylo"
+  # MOZ_UPDATE_CHANNEL isn't always set.  It cannot use to detect as trunk.
+  if [ `tail -1 "$topsrcdir/config/milestone.txt" | grep 'a1'` ] ; then
+    . "$topsrcdir/build/mozconfig.stylo"
+  fi
 fi
 
 MOZ_AUTOMATION_L10N_CHECK=0
 . "$topsrcdir/build/mozconfig.common"
 
 # For actual Android builds in TaskCluster, the system image is Debian,
 # and we use the Java JRE/JDK from the system, as well as the system
 # GCC for the host compiler.  l10n builds are still special, however: