diff --git a/core/config.mk b/core/config.mk
index bce5de85d..daaa54ee8 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -542,6 +542,11 @@ ifndef USE_D8
   USE_D8 := true
 endif
 
+# Default R8 behavior when USE_R8 is not specified.
+ifndef USE_R8
+  USE_R8 := false
+endif
+
 #
 # Tools that are prebuilts for TARGET_BUILD_APPS
 #