diff --git a/core/Makefile b/core/Makefile
index 7fa7a6b..6602a29 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -91,9 +91,7 @@
 
 ifdef has_dup_copy_headers
   has_dup_copy_headers :=
-  ifneq ($(BUILD_BROKEN_DUP_COPY_HEADERS),true)
-    $(error duplicate header copies are no longer allowed. For more information about headers, see: https://android.googlesource.com/platform/build/soong/+/master/docs/best_practices.md#headers)
-  endif
+  $(error duplicate header copies are no longer allowed. For more information about headers, see: https://android.googlesource.com/platform/build/soong/+/master/docs/best_practices.md#headers)
 endif
 
 # -----------------------------------------------------------------
diff --git a/core/board_config.mk b/core/board_config.mk
index 58f636a..bfce087 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -86,7 +86,6 @@
 
 _build_broken_var_list := \
   BUILD_BROKEN_ANDROIDMK_EXPORTS \
-  BUILD_BROKEN_DUP_COPY_HEADERS \
   BUILD_BROKEN_DUP_RULES \
   BUILD_BROKEN_ENG_DEBUG_TAGS \
   BUILD_BROKEN_USES_NETWORK \
diff --git a/core/config.mk b/core/config.mk
index a297f68..386c64e 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -96,6 +96,7 @@
 $(KATI_obsolete_var TARGET_ROOT_OUT_SBIN,/sbin has been removed, use /system/bin instead)
 $(KATI_obsolete_var TARGET_ROOT_OUT_SBIN_UNSTRIPPED,/sbin has been removed, use /system/bin instead)
 $(KATI_obsolete_var BUILD_BROKEN_PHONY_TARGETS)
+$(KATI_obsolete_var BUILD_BROKEN_DUP_COPY_HEADERS)
 
 # This is marked as obsolete in envsetup.mk after reading the BoardConfig.mk
 $(KATI_deprecate_export It is a global setting. See $(CHANGES_URL)#export_keyword)