diff --git a/core/product.mk b/core/product.mk
index ca65948..39c9eb7 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -447,6 +447,8 @@
 
 _product_single_value_vars += PRODUCT_NEXT_RELEASE_HIDE_FLAGGED_API
 
+_product_list_vars += PRODUCT_RELEASE_CONFIG_MAPS
+
 .KATI_READONLY := _product_single_value_vars _product_list_vars
 _product_var_list :=$= $(_product_single_value_vars) $(_product_list_vars)
 
diff --git a/core/release_config.mk b/core/release_config.mk
index b72ee89..5993e85 100644
--- a/core/release_config.mk
+++ b/core/release_config.mk
@@ -52,6 +52,15 @@
         ) \
     )
 
+# PRODUCT_RELEASE_CONFIG_MAPS is set by Soong using an initial run of product
+# config to capture only the list of config maps needed by the build.
+# Keep them in the order provided, but remove duplicates.
+$(foreach map,$(PRODUCT_RELEASE_CONFIG_MAPS), \
+    $(if $(filter $(map),$(config_map_files)),,$(eval config_map_files += $(map))) \
+)
+
+# Declare or extend a release-config.
+#
 # $1 config name
 # $2 release config files
 define declare-release-config
@@ -63,10 +72,24 @@
     $(eval _all_release_configs.$(strip $(1)).FILES := $(_all_release_configs.$(strip $(1)).FILES) $(strip $(2)))
 endef
 
-# Include the config map files
+# Include the config map files and populate _flag_declaration_files.
+_flag_declaration_files :=
 $(foreach f, $(config_map_files), \
+    $(eval FLAG_DECLARATION_FILES:= ) \
     $(eval _included := $(f)) \
     $(eval include $(f)) \
+    $(eval _flag_declaration_files += $(FLAG_DECLARATION_FILES)) \
+)
+FLAG_DECLARATION_FILES :=
+
+# Make sure that the flag definitions are included for vendor/google builds.
+# This decouples the change in vendor/google/release/release_config_map.mk
+# from this logic change.
+# TODO: Remove this once the vendor/google FLAG_DECLARATION_FILES change is there.
+$(if $(wildcard vendor/google/release/release_config_map.mk),\
+  $(if $(filter vendor/google/release/build_flags.bzl,$(_flag_declaration_files)),,\
+    $(eval _flag_declaration_files := vendor/google/release/build_flags.bzl $(_flag_declaration_files)) \
+  ) \
 )
 
 # If TARGET_RELEASE is set, fail if there is no matching release config
@@ -78,7 +101,11 @@
 else
     # Choose flag files
     # Don't sort this, use it in the order they gave us.
-    flag_value_files := $(_all_release_configs.$(TARGET_RELEASE).FILES)
+    # Do allow duplicate entries, retaining only the first usage.
+    flag_value_files :=
+    $(foreach f,$(_all_release_configs.$(TARGET_RELEASE).FILES), \
+      $(if $(filter $(f),$(flag_value_files)),,$(eval flag_value_files += $(f)))\
+    )
 endif
 else
 # Useful for finding scripts etc that aren't passing or setting TARGET_RELEASE
@@ -121,21 +148,8 @@
 # that we chose from the config map above.  Then we run that, and load the
 # results of that into the make environment.
 
-# If this is a google source tree, restrict it to only the one file
-# which has OWNERS control.  If it isn't let others define their own.
-# TODO: Remove wildcard for build/release one when all branch manifests
-# have updated.
-flag_declaration_files := $(wildcard build/release/build_flags.bzl) \
-    $(if $(wildcard vendor/google/release/build_flags.bzl), \
-        vendor/google/release/build_flags.bzl, \
-        $(sort \
-            $(wildcard device/*/release/build_flags.bzl) \
-            $(wildcard device/*/*/release/build_flags.bzl) \
-            $(wildcard vendor/*/release/build_flags.bzl) \
-            $(wildcard vendor/*/*/release/build_flags.bzl) \
-        ) \
-    )
-
+# _flag_declaration_files is the combined list of FLAG_DECLARATION_FILES set by
+# release_config_map.mk files above.
 
 # Because starlark can't find files with $(wildcard), write an entrypoint starlark script that
 # contains the result of the above wildcards for the starlark code to use.
@@ -145,8 +159,8 @@
 _c+=$(newline)$(space)d = dict(d)
 _c+=$(newline)$(space)d[k] = v
 _c+=$(newline)$(space)return d
-_c+=$(foreach f,$(flag_declaration_files),$(newline)load("$(f)", flags_$(call filename_to_starlark,$(f)) = "flags"))
-_c+=$(newline)all_flags = [] $(foreach f,$(flag_declaration_files),+ [add(x, "declared_in", "$(f)") for x in flags_$(call filename_to_starlark,$(f))])
+_c+=$(foreach f,$(_flag_declaration_files),$(newline)load("$(f)", flags_$(call filename_to_starlark,$(f)) = "flags"))
+_c+=$(newline)all_flags = [] $(foreach f,$(_flag_declaration_files),+ [add(x, "declared_in", "$(f)") for x in flags_$(call filename_to_starlark,$(f))])
 _c+=$(foreach f,$(flag_value_files),$(newline)load("//$(f)", values_$(call filename_to_starlark,$(f)) = "values"))
 _c+=$(newline)all_values = [] $(foreach f,$(flag_value_files),+ [add(x, "set_in", "$(f)") for x in values_$(call filename_to_starlark,$(f))])
 _c+=$(newline)variables_to_export_to_make = release_config(all_flags, all_values)