diff --git a/core/envsetup.mk b/core/envsetup.mk
index 860ce79..8887ddc 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -30,14 +30,13 @@
 # In order to avoid running starlark every time the stamp file is checked, we use
 # $(KATI_shell_no_rerun). Then, to make sure that we actually do rerun kati when
 # modifying the starlark files, we add the starlark files to the kati stamp file with
-# $(KATI_extra_file_deps). This behavior can be modified by passing a list of starlark files
-# to exclude from the dependency list as $(2)
+# $(KATI_extra_file_deps).
 define run-starlark
 $(eval _starlark_results := $(OUT_DIR)/starlark_results/$(subst /,_,$(1)).mk)
 $(KATI_shell_no_rerun mkdir -p $(OUT_DIR)/starlark_results && $(OUT_DIR)/rbcrun --mode=make $(1) >$(_starlark_results) && touch -t 200001010000 $(_starlark_results))
 $(if $(filter-out 0,$(.SHELLSTATUS)),$(error Starlark failed to run))
 $(eval include $(_starlark_results))
-$(KATI_extra_file_deps $(filter-out $(2),$(LOADED_STARLARK_FILES)))
+$(KATI_extra_file_deps $(LOADED_STARLARK_FILES))
 $(eval LOADED_STARLARK_FILES :=)
 $(eval _starlark_results :=)
 endef
diff --git a/core/release_config.bzl b/core/release_config.bzl
deleted file mode 100644
index e73c90f..0000000
--- a/core/release_config.bzl
+++ /dev/null
@@ -1,90 +0,0 @@
-# Copyright (C) 2023 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# Partitions that get build system flag summaries
-_flag_partitions = [
-    "product",
-    "system",
-    "system_ext",
-    "vendor",
-]
-
-def _combine_dicts_no_duplicate_keys(dicts):
-    result = {}
-    for d in dicts:
-        for k, v in d.items():
-            if k in result:
-                fail("Duplicate key: " + k)
-            result[k] = v
-    return result
-
-def release_config(target_release, flag_definitions, config_maps, fail_if_no_release_config = True):
-    result = {
-        "_ALL_RELEASE_FLAGS": [flag.name for flag in flag_definitions],
-    }
-    all_flags = {}
-    for flag in flag_definitions:
-        if sorted(dir(flag)) != ["default", "name", "partitions"]:
-            fail("Flag structs must contain 3 fields: name, partitions, and default")
-        if not flag.partitions:
-            fail("At least 1 partition is required")
-        for partition in flag.partitions:
-            if partition == "all":
-                if len(flag.partitions) > 1:
-                    fail("\"all\" can't be combined with other partitions: " + str(flag.partitions))
-            elif partition not in _flag_partitions:
-                fail("Invalid partition: " + flag.partition + ", allowed partitions: " + str(_flag_partitions))
-        if not flag.name.startswith("RELEASE_"):
-            fail("Release flag names must start with RELEASE_")
-        if " " in flag.name or "\t" in flag.name or "\n" in flag.name:
-            fail("Flag names must not contain whitespace.")
-        if flag.name in all_flags:
-            fail("Duplicate declaration of flag " + flag.name)
-        all_flags[flag.name] = True
-
-        default = flag.default
-        if type(default) == "bool":
-            default = "true" if default else ""
-
-        result["_ALL_RELEASE_FLAGS." + flag.name + ".PARTITIONS"] = flag.partitions
-        result["_ALL_RELEASE_FLAGS." + flag.name + ".DEFAULT"] = default
-        result["_ALL_RELEASE_FLAGS." + flag.name + ".VALUE"] = default
-
-    # If TARGET_RELEASE is set, fail if there is no matching release config
-    # If it isn't set, no release config files will be included and all flags
-    # will get their default values.
-    if target_release:
-        config_map = _combine_dicts_no_duplicate_keys(config_maps)
-        if target_release not in config_map:
-            fail("No release config found for TARGET_RELEASE: " + target_release + ". Available releases are: " + str(config_map.keys()))
-        release_config = config_map[target_release]
-        if sorted(dir(release_config)) != ["flags", "release_version"]:
-            fail("A release config must be a struct with a flags and release_version fields")
-        result["_RELEASE_VERSION"] = release_config.release_version
-        for flag in release_config.flags:
-            if sorted(dir(release_config)) != ["name", "value"]:
-                fail("A flag be a struct with name and value fields")
-            if flag.name not in all_flags:
-                fail("Undeclared build flag: " + flag.name)
-            value = flag.value
-            if type(value) == "bool":
-                value = "true" if value else ""
-            result["_ALL_RELEASE_FLAGS." + flag.name + ".VALUE"] = value
-    elif fail_if_no_release_config:
-        fail("FAIL_IF_NO_RELEASE_CONFIG was set and TARGET_RELEASE was not")
-    else:
-        # No TARGET_RELEASE means release version 0
-        result["_RELEASE_VERSION"] = 0
-
-    return result
diff --git a/core/release_config.mk b/core/release_config.mk
index 621c7d1..fdfc6a0 100644
--- a/core/release_config.mk
+++ b/core/release_config.mk
@@ -12,45 +12,78 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Partitions that get build system flag summaries
+_FLAG_PARTITIONS := system vendor system_ext product
+
+# All possible release flags. Defined in the build_flags.mk files
+# throughout the tree
+_ALL_RELEASE_FLAGS :=
+
+# -----------------------------------------------------------------
+# Choose the flag files
+# Do this first, because we're going to unset TARGET_RELEASE before
+# including anyone, so they don't start making conditionals based on it.
+
 # 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, \
+config_map_files := $(wildcard build/release/release_config_map.mk) \
+    $(if $(wildcard vendor/google/release/release_config_map.mk), \
+        vendor/google/release/release_config_map.mk, \
         $(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) \
-        ) \
-    )
-config_map_files := $(wildcard build/release/release_config_map.bzl) \
-    $(if $(wildcard vendor/google/release/release_config_map.bzl), \
-        vendor/google/release/release_config_map.bzl, \
-        $(sort \
-            $(wildcard device/*/release/release_config_map.bzl) \
-            $(wildcard device/*/*/release/release_config_map.bzl) \
-            $(wildcard vendor/*/release/release_config_map.bzl) \
-            $(wildcard vendor/*/*/release/release_config_map.bzl) \
+            $(wildcard device/*/release/release_config_map.mk) \
+            $(wildcard device/*/*/release/release_config_map.mk) \
+            $(wildcard vendor/*/release/release_config_map.mk) \
+            $(wildcard vendor/*/*/release/release_config_map.mk) \
         ) \
     )
 
-# Because starlark can't find files with $(wildcard), write an entrypoint starlark script that
-# contains the result of the above wildcards for the starlark code to use.
-filename_to_starlark=$(subst /,_,$(subst .,_,$(1)))
-_c:=load("//build/make/core/release_config.bzl", "release_config")
-_c+=$(foreach f,$(flag_declaration_files),$(newline)load("//$(f)", flags_$(call filename_to_starlark,$(f)) = "flags"))
-_c+=$(foreach f,$(config_map_files),$(newline)load("//$(f)", config_maps_$(call filename_to_starlark,$(f)) = "config_maps"))
-_c+=$(newline)all_flags = [] $(foreach f,$(flag_declaration_files),+ flags_$(call filename_to_starlark,$(f)))
-_c+=$(newline)all_config_maps = [$(foreach f,$(config_map_files),config_maps_$(call filename_to_starlark,$(f))$(comma))]
-_c+=$(newline)target_release = "$(TARGET_RELEASE)"
-_c+=$(newline)fail_if_no_release_config = True if "$(FAIL_IF_NO_RELEASE_CONFIG)" else False
-_c+=$(newline)variables_to_export_to_make = release_config(target_release, all_flags, all_config_maps, fail_if_no_release_config)
-$(file >$(OUT_DIR)/release_config_entrypoint.bzl,$(_c))
-_c:=
-filename_to_starlark:=
+# $1 config name
+# $2 release config files
+define declare-release-config
+    $(eval # No duplicates)
+    $(if $(filter $(_all_release_configs), $(strip $(1))), \
+        $(error declare-release-config: config $(strip $(1)) declared in: $(_included) Previously declared here: $(_all_release_configs.$(strip $(1)).DECLARED_IN)) \
+    )
+    $(eval # Must have release config files)
+    $(if $(strip $(2)),,  \
+        $(error declare-release-config: config $(strip $(1)) must have release config files) \
+    )
+    $(eval _all_release_configs := $(sort $(_all_release_configs) $(strip $(1))))
+    $(eval _all_release_configs.$(strip $(1)).DECLARED_IN := $(_included))
+    $(eval _all_release_configs.$(strip $(1)).FILES := $(strip $(2)))
+endef
+
+# Include the config map files
+$(foreach f, $(config_map_files), \
+    $(eval _included := $(f)) \
+    $(eval include $(f)) \
+)
+
+# If TARGET_RELEASE is set, fail if there is no matching release config
+# If it isn't set, no release config files will be included and all flags
+# will get their default values.
+ifneq ($(TARGET_RELEASE),)
+ifeq ($(filter $(_all_release_configs), $(TARGET_RELEASE)),)
+    $(error No release config found for TARGET_RELEASE: $(TARGET_RELEASE). Available releases are: $(_all_release_configs))
+else
+    # Choose flag files
+    # Don't sort this, use it in the order they gave us.
+    _release_config_files := $(_all_release_configs.$(TARGET_RELEASE).FILES)
+endif
+else
+# Useful for finding scripts etc that aren't passing or setting TARGET_RELEASE
+ifneq ($(FAIL_IF_NO_RELEASE_CONFIG),)
+    $(error FAIL_IF_NO_RELEASE_CONFIG was set and TARGET_RELEASE was not)
+endif
+_release_config_files :=
+endif
+
+# Unset variables so they can't use it
+define declare-release-config
+$(error declare-release-config can only be called from inside release_config_map.mk files)
+endef
 
 # TODO: Remove this check after enough people have sourced lunch that we don't
 # need to worry about it trying to do get_build_vars TARGET_RELEASE. Maybe after ~9/2023
@@ -63,7 +96,127 @@
 endif
 .KATI_READONLY := TARGET_RELEASE
 
-# Exclude the entrypoint file as a dependency (by passing it as the 2nd argument) so that we don't
-# rerun kati every build. Kati will replay the $(file) command that generates it every build,
-# updating its timestamp.
-$(call run-starlark,$(OUT_DIR)/release_config_entrypoint.bzl,$(OUT_DIR)/release_config_entrypoint.bzl)
+$(foreach config, $(_all_release_configs), \
+    $(eval _all_release_configs.$(config).DECLARED_IN:= ) \
+    $(eval _all_release_configs.$(config).FILES:= ) \
+)
+_all_release_configs:=
+config_map_files:=
+
+# -----------------------------------------------------------------
+# Declare the flags
+
+# $1 partition(s)
+# $2 flag name. Must start with RELEASE_
+# $3 default. True or false
+define declare-build-flag
+    $(if $(filter-out all $(_FLAG_PARTITIONS), $(strip $(1))), \
+        $(error declare-build-flag: invalid partitions: $(strip $(1))) \
+    )
+    $(if $(and $(filter all,$(strip $(1))),$(filter-out all, $(strip $(1)))), \
+        $(error declare-build-flag: "all" can't be combined with other partitions: $(strip $(1))), \
+        $(eval declare-build-flag.partition := $(_FLAG_PARTITIONS)) \
+    )
+    $(if $(filter-out RELEASE_%, $(strip $(2))), \
+        $(error declare-build-flag: Release flag names must start with RELEASE_: $(strip $(2))) \
+    )
+    $(eval _ALL_RELEASE_FLAGS += $(strip $(2)))
+    $(foreach partition, $(declare-build-flag.partition), \
+        $(eval _ALL_RELEASE_FLAGS.PARTITIONS.$(partition) := $(sort \
+            $(_ALL_RELEASE_FLAGS.PARTITIONS.$(partition)) $(strip $(2)))) \
+    )
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).PARTITIONS := $(declare-build-flag.partition))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).DEFAULT := $(strip $(3)))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).DECLARED_IN := $(_included))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).VALUE := $(strip $(3)))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).SET_IN := $(_included))
+    $(eval declare-build-flag.partition:=)
+endef
+
+
+# Choose the files
+# 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.
+flag_declaration_files := $(wildcard build/release/build_flags.mk) \
+    $(if $(wildcard vendor/google/release/build_flags.mk), \
+        vendor/google/release/build_flags.mk, \
+        $(sort \
+            $(wildcard device/*/release/build_flags.mk) \
+            $(wildcard device/*/*/release/build_flags.mk) \
+            $(wildcard vendor/*/release/build_flags.mk) \
+            $(wildcard vendor/*/*/release/build_flags.mk) \
+        ) \
+    )
+
+# Include the files
+$(foreach f, $(flag_declaration_files), \
+    $(eval _included := $(f)) \
+    $(eval include $(f)) \
+)
+
+# Don't let anyone declare build flags after here
+define declare-build-flag
+$(error declare-build-flag can only be called from inside flag definition files.)
+endef
+
+# No more flags from here on
+.KATI_READONLY := _ALL_RELEASE_FLAGS
+
+# -----------------------------------------------------------------
+# Set the flags
+
+# $(1): Flag name. Must start with RELEASE_ and have been defined by declare-build-flag
+# $(2): Value. True or false
+define set-build-flag
+    $(if $(filter-out $(_ALL_RELEASE_FLAGS), $(strip $(1))), \
+        $(error set-build-flag: Undeclared build flag: $(strip $(1))) \
+    )
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(1)).VALUE := $(strip $(2)))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(1)).SET_IN := $(_included))
+endef
+
+# This writes directly to a file so that the version never exists in make for
+# people to write conditionals upon.
+define set-release-version
+    $(eval _RELEASE_VERSION := $(strip $(1)))
+endef
+
+# Include the files (if there are any)
+ifneq ($(strip $(_release_config_files)),)
+    $(foreach f, $(_release_config_files), \
+        $(eval _included := $(f)) \
+        $(eval include $(f)) \
+    )
+else
+    # No TARGET_RELEASE means release version 0
+    $(call set-release-version, 0)
+endif
+
+
+ifeq ($(_RELEASE_VERSION)),)
+    $(error No release config file called set-release-version. Included files were: $(_release_config_files))
+endif
+
+# Don't let anyone declare build flags after here
+define set-build-flag
+$(error set-build-flag can only be called from inside release config files.)
+endef
+
+# Don't let anyone set the release version after here
+define set-release-version
+$(error set-release-version can only be called from inside release config files.)
+endef
+
+# Set the flag values, and don't allow any one to modify them.
+$(foreach flag, $(_ALL_RELEASE_FLAGS), \
+    $(eval $(flag) := $(_ALL_RELEASE_FLAGS.$(flag).VALUE)) \
+    $(eval .KATI_READONLY := $(flag)) \
+)
+
+
+# -----------------------------------------------------------------
+# Clear out vars
+flag_declaration_files:=
+flag_files:=
+_included:=
+_release_config_files:=