diff --git a/core/board_config.mk b/core/board_config.mk
index ac0f27d..e58b123 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -508,8 +508,16 @@
 # APEXes are by default flattened, i.e. non-updatable.
 # It can be unflattened (and updatable) by inheriting from
 # updatable_apex.mk
-ifeq (,$(TARGET_FLATTEN_APEX))
-TARGET_FLATTEN_APEX := true
+#
+# APEX flattening can also be forcibly enabled (resp. disabled) by
+# setting OVERRIDE_TARGET_FLATTEN_APEX to true (resp. false), e.g. by
+# setting the OVERRIDE_TARGET_FLATTEN_APEX environment variable.
+ifdef OVERRIDE_TARGET_FLATTEN_APEX
+  TARGET_FLATTEN_APEX := $(OVERRIDE_TARGET_FLATTEN_APEX)
+else
+  ifeq (,$(TARGET_FLATTEN_APEX))
+    TARGET_FLATTEN_APEX := true
+  endif
 endif
 
 ifeq (,$(TARGET_BUILD_APPS))
diff --git a/target/product/updatable_apex.mk b/target/product/updatable_apex.mk
index 038f66e..9b87165 100644
--- a/target/product/updatable_apex.mk
+++ b/target/product/updatable_apex.mk
@@ -16,6 +16,8 @@
 
 # Inherit this when the target needs to support updating APEXes
 
-PRODUCT_PROPERTY_OVERRIDES := ro.apex.updatable=true
-PRODUCT_PACKAGES := com.android.apex.cts.shim.v1_prebuilt
-TARGET_FLATTEN_APEX := false
+ifneq ($(OVERRIDE_TARGET_FLATTEN_APEX),true)
+  PRODUCT_PACKAGES := com.android.apex.cts.shim.v1_prebuilt
+  PRODUCT_PROPERTY_OVERRIDES := ro.apex.updatable=true
+  TARGET_FLATTEN_APEX := false
+endif