diff --git a/core/envsetup.mk b/core/envsetup.mk
index f78ecb4..167fed9 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -93,6 +93,7 @@
 endif
 
 TARGET_BUILD_APPS ?=
+TARGET_BUILD_UNBUNDLED_IMAGE ?=
 
 # Set to true for an unbundled build, i.e. a build without
 # support for platform targets like the system image. This also
@@ -107,11 +108,19 @@
   TARGET_BUILD_UNBUNDLED := true
 endif
 
+# TARGET_BUILD_UNBUNDLED_IMAGE also implies unbundled build.
+# (i.e. it targets to only unbundled image, such as the vendor image,
+# ,or the product image). 
+ifneq ($(TARGET_BUILD_UNBUNDLED_IMAGE),)
+  TARGET_BUILD_UNBUNDLED := true
+endif
+
 .KATI_READONLY := \
   TARGET_PRODUCT \
   TARGET_BUILD_VARIANT \
   TARGET_BUILD_APPS \
   TARGET_BUILD_UNBUNDLED \
+  TARGET_BUILD_UNBUNDLED_IMAGE \
 
 # ---------------------------------------------------------------
 # Set up configuration for host machine.  We don't do cross-