diff --git a/Deprecation.md b/Deprecation.md
index 2f936e354..0cf3a0193 100644
--- a/Deprecation.md
+++ b/Deprecation.md
@@ -14,19 +14,19 @@ have any problems converting, please contact us via:
 
 | Module type                      | State     |
 | -------------------------------- | --------- |
-| `BUILD_AUX_EXECUTABLE`           | Error     |
-| `BUILD_AUX_STATIC_LIBRARY`       | Error     |
+| `BUILD_AUX_EXECUTABLE`           | Obsolete  |
+| `BUILD_AUX_STATIC_LIBRARY`       | Obsolete  |
 | `BUILD_COPY_HEADERS`             | Error     |
 | `BUILD_HOST_EXECUTABLE`          | Error     |
 | `BUILD_HOST_FUZZ_TEST`           | Error     |
 | `BUILD_HOST_NATIVE_TEST`         | Error     |
 | `BUILD_HOST_SHARED_LIBRARY`      | Error     |
-| `BUILD_HOST_SHARED_TEST_LIBRARY` | Error     |
+| `BUILD_HOST_SHARED_TEST_LIBRARY` | Obsolete  |
 | `BUILD_HOST_STATIC_LIBRARY`      | Error     |
 | `BUILD_HOST_STATIC_TEST_LIBRARY` | Error     |
 | `BUILD_HOST_TEST_CONFIG`         | Error     |
 | `BUILD_NATIVE_BENCHMARK`         | Error     |
-| `BUILD_SHARED_TEST_LIBRARY`      | Error     |
+| `BUILD_SHARED_TEST_LIBRARY`      | Obsolete  |
 | `BUILD_STATIC_TEST_LIBRARY`      | Error     |
 | `BUILD_TARGET_TEST_CONFIG`       | Error     |
 | `BUILD_*`                        | Available |
diff --git a/core/aux_config.mk b/core/aux_config.mk
deleted file mode 100644
index 10d2536bc..000000000
--- a/core/aux_config.mk
+++ /dev/null
@@ -1,187 +0,0 @@
-variant_list := $(filter AUX-%,$(MAKECMDGOALS))
-
-ifdef variant_list
-AUX_OS_VARIANT_LIST := $(patsubst AUX-%,%,$(variant_list))
-else
-AUX_OS_VARIANT_LIST := $(TARGET_AUX_OS_VARIANT_LIST)
-endif
-
-# exclude AUX targets from build
-ifeq ($(AUX_OS_VARIANT_LIST),none)
-AUX_OS_VARIANT_LIST :=
-endif
-
-# temporary workaround to support external toolchain
-ifeq ($(NANOHUB_TOOLCHAIN),)
-AUX_OS_VARIANT_LIST :=
-endif
-
-# setup toolchain paths for various CPU architectures
-# this one will come from android prebuilts eventually
-AUX_TOOLCHAIN_cortexm4 := $(NANOHUB_TOOLCHAIN)
-ifeq ($(wildcard $(AUX_TOOLCHAIN_cortexm4)gcc),)
-AUX_TOOLCHAIN_cortexm4:=
-endif
-
-# there is no MAKE var that defines path to HOST toolchain
-# all the interesting paths are hardcoded in soong, and are not available from here
-# There is no other way but to hardcode them again, as we may need host x86 toolcain for AUX
-ifeq ($(HOST_OS),linux)
-AUX_TOOLCHAIN_x86 := prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.15-4.8/bin/x86_64-linux-
-endif
-
-# setup AUX globals
-AUX_SHLIB_SUFFIX := .so
-AUX_GLOBAL_ARFLAGS := crsPD
-AUX_STATIC_LIB_SUFFIX := .a
-
-# Load ever-lasting "indexed" version of AUX variant environment; it is treated as READ-ONLY from this
-# moment on.
-#
-# $(1) - variant
-# no return value
-define aux-variant-setup-paths
-$(eval AUX_OUT_ROOT_$(1) := $(PRODUCT_OUT)/aux/$(1)) \
-$(eval AUX_COMMON_OUT_ROOT_$(1) := $(AUX_OUT_ROOT_$(1))/common) \
-$(eval AUX_OUT_$(1) := $(AUX_OUT_ROOT_$(1))/$(AUX_OS_$(1))-$(AUX_ARCH_$(1))-$(AUX_CPU_$(1))) \
-$(eval AUX_OUT_INTERMEDIATES_$(1) := $(AUX_OUT_$(1))/obj) \
-$(eval AUX_OUT_COMMON_INTERMEDIATES_$(1) := $(AUX_COMMON_OUT_ROOT_$(1))/obj) \
-$(eval AUX_OUT_HEADERS_$(1) := $(AUX_OUT_INTERMEDIATES_$(1))/include) \
-$(eval AUX_OUT_NOTICE_FILES_$(1) := $(AUX_OUT_INTERMEDIATES_$(1))/NOTICE_FILES) \
-$(eval AUX_OUT_FAKE_$(1) := $(AUX_OUT_$(1))/fake_packages) \
-$(eval AUX_OUT_GEN_$(1) := $(AUX_OUT_$(1))/gen) \
-$(eval AUX_OUT_COMMON_GEN_$(1) := $(AUX_COMMON_OUT_ROOT_$(1))/gen) \
-$(eval AUX_OUT_EXECUTABLES_$(1) := $(AUX_OUT_$(1))/bin) \
-$(eval AUX_OUT_UNSTRIPPED_$(1) := $(AUX_OUT_$(1))/symbols)
-endef
-
-# Copy "indexed" AUX environment for given VARIANT into
-# volatile not-indexed set of variables for simplicity of access.
-# Injection of index support throughout the build system is suboptimal
-# hence volatile environment is constructed
-# Unlike HOST*, TARGET* variables, AUX* variables are NOT read-only, but their
-# indexed versions are.
-#
-# $(1) - variant
-# no return value
-define aux-variant-load-env
-$(eval AUX_OS_VARIANT:=$(1)) \
-$(eval AUX_OS:=$(AUX_OS_$(1))) \
-$(eval AUX_ARCH:=$(AUX_ARCH_$(1))) \
-$(eval AUX_SUBARCH:=$(AUX_SUBARCH_$(1))) \
-$(eval AUX_CPU:=$(AUX_CPU_$(1))) \
-$(eval AUX_OS_PATH:=$(AUX_OS_PATH_$(1))) \
-$(eval AUX_OUT_ROOT := $(AUX_OUT_ROOT_$(1))) \
-$(eval AUX_COMMON_OUT_ROOT := $(AUX_COMMON_OUT_ROOT_$(1))) \
-$(eval AUX_OUT := $(AUX_OUT_$(1))) \
-$(eval AUX_OUT_INTERMEDIATES := $(AUX_OUT_INTERMEDIATES_$(1))) \
-$(eval AUX_OUT_COMMON_INTERMEDIATES := $(AUX_OUT_COMMON_INTERMEDIATES_$(1))) \
-$(eval AUX_OUT_HEADERS := $(AUX_OUT_HEADERS_$(1))) \
-$(eval AUX_OUT_NOTICE_FILES := $(AUX_OUT_NOTICE_FILES_$(1))) \
-$(eval AUX_OUT_FAKE := $(AUX_OUT_FAKE_$(1))) \
-$(eval AUX_OUT_GEN := $(AUX_OUT_GEN_$(1))) \
-$(eval AUX_OUT_COMMON_GEN := $(AUX_OUT_COMMON_GEN_$(1))) \
-$(eval AUX_OUT_EXECUTABLES := $(AUX_OUT_EXECUTABLES_$(1))) \
-$(eval AUX_OUT_UNSTRIPPED := $(AUX_OUT_UNSTRIPPED_$(1)))
-endef
-
-# given a variant:path pair, load the variant conviguration with aux-variant-setup-paths from file
-# this is a build system extension mechainsm, since configuration typically resides in non-build
-# project space
-#
-# $(1) - variant:path pair
-# $(2) - file suffix
-# no return value
-define aux-variant-import-from-pair
-$(eval _pair := $(subst :, ,$(1))) \
-$(eval _name:=$(word 1,$(_pair))) \
-$(eval _path:=$(word 2,$(_pair))) \
-$(eval include $(_path)/$(_name)$(2)) \
-$(eval AUX_OS_VARIANT_LIST_$(AUX_OS_$(1)):=) \
-$(call aux-variant-setup-paths,$(_name)) \
-$(eval AUX_ALL_VARIANTS += $(_name)) \
-$(eval AUX_ALL_OSES := $(filter-out $(AUX_OS_$(_name)),$(AUX_ALL_OSES)) $(AUX_OS_$(_name))) \
-$(eval AUX_ALL_CPUS := $(filter-out $(AUX_CPU_$(_name)),$(AUX_ALL_CPUS)) $(AUX_CPU_$(_name))) \
-$(eval AUX_ALL_ARCHS := $(filter-out $(AUX_ARCH_$(_name)),$(AUX_ALL_ARCHS)) $(AUX_ARCH_$(_name))) \
-$(eval AUX_ALL_SUBARCHS := $(filter-out $(AUX_SUBARCH_$(_name)),$(AUX_ALL_SUBARCHS)) $(AUX_SUBARCH_$(_name)))
-endef
-
-# Load system configuration referenced by AUX variant config;
-# this is a build extension mechanism; typically system config
-# resides in a non-build projects;
-# system config may define new rules and globally visible BUILD*
-# includes to support project-specific build steps and toolchains
-# MAintains list of valiants that reference this os config in OS "indexed" var
-# this facilitates multivariant build of the OS (or whataver it is the name of common component these variants share)
-#
-# $(1) - variant
-# no return value
-define aux-import-os-config
-$(eval _aioc_os := $(AUX_OS_$(1))) \
-$(eval AUX_OS_PATH_$(1) := $(patsubst $(_aioc_os):%,%,$(filter $(_aioc_os):%,$(AUX_ALL_OS_PATHS)))) \
-$(eval _aioc_os_cfg := $(AUX_OS_PATH_$(1))/$(_aioc_os)$(os_sfx)) \
-$(if $(wildcard $(_aioc_os_cfg)),,$(error AUX '$(_aioc_os)' OS config file [$(notdir $(_aioc_os_cfg))] required by AUX variant '$(1)' does not exist)) \
-$(if $(filter $(_aioc_os),$(_os_list)),,$(eval include $(_aioc_os_cfg))) \
-$(eval AUX_OS_VARIANT_LIST_$(_aioc_os) += $(1)) \
-$(eval _os_list += $(_aioc_os))
-endef
-
-# make sure that AUX config variables are minimally sane;
-# as a bare minimum they must contain the vars described by aux_env
-# Generate error if requirement is not met.
-#
-#$(1) - variant
-# no return value
-define aux-variant-validate
-$(eval _all:=) \
-$(eval _req:=$(addsuffix _$(1),$(aux_env))) \
-$(foreach var,$(_req),$(eval _all += $(var))) \
-$(eval _missing := $(filter-out $(_all),$(_req))) \
-$(if $(_missing),$(error AUX variant $(1) must define vars: $(_missing)))
-endef
-
-AUX_ALL_VARIANTS :=
-AUX_ALL_OSES :=
-AUX_ALL_CPUS :=
-AUX_ALL_ARCHS :=
-AUX_ALL_SUBARCHS :=
-
-variant_sfx :=_aux_variant_config.mk
-os_sfx :=_aux_os_config.mk
-
-ifdef AUX_OS_VARIANT_LIST
-
-config_roots := $(wildcard device vendor)
-all_configs :=
-ifdef config_roots
-all_configs := $(sort $(shell find $(config_roots) -maxdepth 4 -name '*$(variant_sfx)' -o -name '*$(os_sfx)'))
-endif
-all_os_configs := $(filter %$(os_sfx),$(all_configs))
-all_variant_configs := $(filter %$(variant_sfx),$(all_configs))
-
-AUX_ALL_OS_PATHS := $(foreach f,$(all_os_configs),$(patsubst %$(os_sfx),%,$(notdir $(f))):$(patsubst %/,%,$(dir $(f))))
-AUX_ALL_OS_VARIANT_PATHS := $(foreach f,$(all_variant_configs),$(patsubst %$(variant_sfx),%,$(notdir $(f))):$(patsubst %/,%,$(dir $(f))))
-
-my_variant_pairs := $(foreach v,$(AUX_OS_VARIANT_LIST),$(filter $(v):%,$(AUX_ALL_OS_VARIANT_PATHS)))
-my_missing_variants := $(foreach v,$(AUX_OS_VARIANT_LIST),$(if $(filter $(v):%,$(AUX_ALL_OS_VARIANT_PATHS)),,$(v)))
-
-ifneq ($(strip $(my_missing_variants)),)
-$(error Don't know how to build variant(s): $(my_missing_variants))
-endif
-
-# mandatory variables
-aux_env := AUX_OS AUX_ARCH AUX_SUBARCH AUX_CPU
-
-$(foreach v,$(my_variant_pairs),$(if $(filter $(v),$(AUX_ALL_VARIANTS)),,$(call aux-variant-import-from-pair,$(v),$(variant_sfx))))
-
-ifdef AUX_ALL_VARIANTS
-_os_list :=
-$(foreach v,$(AUX_ALL_VARIANTS),\
-  $(call aux-import-os-config,$(v)) \
-  $(call aux-variant-validate,$(v)) \
-)
-endif
-
-endif # AUX_OS_VARIANT_LIST
-
-INSTALLED_AUX_TARGETS :=
diff --git a/core/aux_executable.mk b/core/aux_executable.mk
deleted file mode 100644
index 5395e6196..000000000
--- a/core/aux_executable.mk
+++ /dev/null
@@ -1,95 +0,0 @@
-# caller might have included aux_toolchain, e.g. if custom build steps are defined
-ifeq ($(LOCAL_IS_AUX_MODULE),)
-include $(BUILD_SYSTEM)/aux_toolchain.mk
-endif
-
-ifeq ($(AUX_BUILD_NOT_COMPATIBLE),)
-
-###########################################################
-## Standard rules for building an executable file.
-##
-## Additional inputs from base_rules.make:
-## None.
-###########################################################
-
-ifeq ($(strip $(LOCAL_MODULE_CLASS)),)
-LOCAL_MODULE_CLASS := EXECUTABLES
-endif
-
-$(call $(aux-executable-hook))
-
-###########################################################
-## Standard rules for building any target-side binaries
-## with dynamic linkage (dynamic libraries or executables
-## that link with dynamic libraries)
-##
-## Files including this file must define a rule to build
-## the target $(linked_module).
-###########################################################
-
-# The name of the target file, without any path prepended.
-# This duplicates logic from base_rules.mk because we need to
-# know its results before base_rules.mk is included.
-include $(BUILD_SYSTEM)/configure_module_stem.mk
-
-intermediates := $(call local-intermediates-dir)
-
-# Define the target that is the unmodified output of the linker.
-# The basename of this target must be the same as the final output
-# binary name, because it's used to set the "soname" in the binary.
-# The includer of this file will define a rule to build this target.
-linked_module := $(intermediates)/LINKED/$(my_built_module_stem)
-
-ALL_ORIGINAL_DYNAMIC_BINARIES += $(linked_module)
-
-# Because AUX_SYMBOL_FILTER_FILE depends on ALL_ORIGINAL_DYNAMIC_BINARIES,
-# the linked_module rules won't necessarily inherit the PRIVATE_
-# variables from LOCAL_BUILT_MODULE.  This tells binary.make to explicitly
-# define the PRIVATE_ variables for linked_module as well as for
-# LOCAL_BUILT_MODULE.
-LOCAL_INTERMEDIATE_TARGETS += $(linked_module)
-
-###################################
-include $(BUILD_SYSTEM)/binary.mk
-###################################
-
-aux_output := $(linked_module)
-
-ifneq ($(LOCAL_CUSTOM_BUILD_STEP_INPUT),)
-ifneq ($(LOCAL_CUSTOM_BUILD_STEP_OUTPUT),)
-
-# injecting custom build steps
-$(LOCAL_CUSTOM_BUILD_STEP_INPUT): $(aux_output)
-	@echo "$(AUX_DISPLAY) custom copy: $(PRIVATE_MODULE) ($@)"
-	@mkdir -p $(dir $@)
-	$(hide) $(copy-file-to-target)
-
-aux_output := $(LOCAL_CUSTOM_BUILD_STEP_OUTPUT)
-
-endif
-endif
-
-$(LOCAL_BUILT_MODULE): $(aux_output)
-	@echo "$(AUX_DISPLAY) final copy: $(PRIVATE_MODULE) ($@)"
-	@mkdir -p $(dir $@)
-	$(hide) $(copy-file-to-target)
-
-INSTALLED_AUX_TARGETS += $(LOCAL_INSTALLED_MODULE)
-
-$(cleantarget): PRIVATE_CLEAN_FILES += \
-    $(linked_module) \
-
-# Define PRIVATE_ variables from global vars
-$(linked_module): PRIVATE_POST_LINK_CMD := $(LOCAL_POST_LINK_CMD)
-
-ifeq ($(LOCAL_FORCE_STATIC_EXECUTABLE),true)
-$(linked_module): $(all_objects) $(all_libraries) $(LOCAL_ADDITIONAL_DEPENDENCIES)
-	$(transform-o-to-aux-static-executable)
-	$(PRIVATE_POST_LINK_CMD)
-else
-$(linked_module): $(all_objects) $(all_libraries) $(LOCAL_ADDITIONAL_DEPENDENCIES)
-	$(transform-o-to-aux-executable)
-	$(PRIVATE_POST_LINK_CMD)
-endif
-
-endif # AUX_BUILD_NOT_COMPATIBLE
diff --git a/core/aux_static_library.mk b/core/aux_static_library.mk
deleted file mode 100644
index d88478d83..000000000
--- a/core/aux_static_library.mk
+++ /dev/null
@@ -1,27 +0,0 @@
-ifeq ($(LOCAL_IS_AUX_MODULE),)
-include $(BUILD_SYSTEM)/aux_toolchain.mk
-endif
-
-ifeq ($(AUX_BUILD_NOT_COMPATIBLE),)
-
-ifeq ($(strip $(LOCAL_MODULE_CLASS)),)
-LOCAL_MODULE_CLASS := STATIC_LIBRARIES
-endif
-ifeq ($(strip $(LOCAL_MODULE_SUFFIX)),)
-LOCAL_MODULE_SUFFIX := .a
-endif
-
-LOCAL_UNINSTALLABLE_MODULE := true
-
-ifneq ($(strip $(LOCAL_MODULE_STEM)$(LOCAL_BUILT_MODULE_STEM)),)
-$(error $(LOCAL_PATH): Cannot set module stem for a library)
-endif
-
-include $(BUILD_SYSTEM)/binary.mk
-
-$(LOCAL_BUILT_MODULE) : PRIVATE_AR := $(AUX_AR)
-$(LOCAL_BUILT_MODULE) : $(built_whole_libraries)
-$(LOCAL_BUILT_MODULE) : $(all_objects)
-	$(transform-o-to-aux-static-lib)
-
-endif # AUX_BUILD_NOT_COMPATIBLE
diff --git a/core/aux_toolchain.mk b/core/aux_toolchain.mk
deleted file mode 100644
index c7102288d..000000000
--- a/core/aux_toolchain.mk
+++ /dev/null
@@ -1,52 +0,0 @@
-###########################################################
-# takes form LOCAL_AUX_TOOLCHAIN_$(LOCAL_AUX_CPU)
-###########################################################
-
-###############################
-# setup AUX environment
-###############################
-
-# shortcuts for targets with a single instance of OS, ARCH, VARIANT, CPU
-AUX_TOOLCHAIN := $(if $(LOCAL_AUX_TOOLCHAIN),$(LOCAL_AUX_TOOLCHAIN),$(AUX_TOOLCHAIN_$(AUX_CPU)))
-AUX_BUILD_NOT_COMPATIBLE:=
-ifeq ($(strip $(AUX_TOOLCHAIN)),)
-  ifeq ($(strip $(AUX_CPU)),)
-    $(warning $(LOCAL_PATH): $(LOCAL_MODULE): Undefined CPU for AUX toolchain)
-    AUX_BUILD_NOT_COMPATIBLE += TOOLCHAIN
-  else
-    $(warning $(LOCAL_PATH): $(LOCAL_MODULE): Undefined AUX toolchain for CPU=$(AUX_CPU))
-    AUX_BUILD_NOT_COMPATIBLE += TOOLCHAIN
-  endif
-endif
-
-AUX_BUILD_NOT_COMPATIBLE += $(foreach var,OS ARCH SUBARCH CPU OS_VARIANT,$(if $(LOCAL_AUX_$(var)),$(if \
-    $(filter $(LOCAL_AUX_$(var)),$(AUX_$(var))),,$(var))))
-
-AUX_BUILD_NOT_COMPATIBLE := $(strip $(AUX_BUILD_NOT_COMPATIBLE))
-
-ifneq ($(AUX_BUILD_NOT_COMPATIBLE),)
-$(info $(LOCAL_PATH): $(LOCAL_MODULE): not compatible: "$(AUX_BUILD_NOT_COMPATIBLE)" with)
-$(info ====> OS=$(AUX_OS) CPU=$(AUX_CPU) ARCH=$(AUX_ARCH) SUBARCH=$(AUX_SUBARCH) OS_VARIANT=$(AUX_OS_VARIANT))
-$(info ====> TOOLCHAIN=$(AUX_TOOLCHAIN))
-endif
-
-AUX_AR := $(AUX_TOOLCHAIN)ar
-AUX_AS := $(AUX_TOOLCHAIN)gcc
-AUX_CC := $(AUX_TOOLCHAIN)gcc
-AUX_CXX := $(AUX_TOOLCHAIN)g++
-AUX_LINKER := $(AUX_TOOLCHAIN)ld
-AUX_OBJCOPY := $(AUX_TOOLCHAIN)objcopy
-AUX_OBJDUMP := $(AUX_TOOLCHAIN)objdump
-
-###############################
-# setup Android environment
-###############################
-
-LOCAL_IS_AUX_MODULE := true
-LOCAL_2ND_ARCH_VAR_PREFIX :=
-LOCAL_CC := $(AUX_CC)
-LOCAL_CXX := $(AUX_CXX)
-LOCAL_NO_DEFAULT_COMPILER_FLAGS := true
-LOCAL_SYSTEM_SHARED_LIBRARIES :=
-LOCAL_CXX_STL := none
-LOCAL_NO_PIC := true
diff --git a/core/base_rules.mk b/core/base_rules.mk
index 1d1c114e9..b1613841f 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -34,7 +34,6 @@ endif
 $(call verify-module-name)
 
 LOCAL_IS_HOST_MODULE := $(strip $(LOCAL_IS_HOST_MODULE))
-LOCAL_IS_AUX_MODULE := $(strip $(LOCAL_IS_AUX_MODULE))
 ifdef LOCAL_IS_HOST_MODULE
   ifneq ($(LOCAL_IS_HOST_MODULE),true)
     $(error $(LOCAL_PATH): LOCAL_IS_HOST_MODULE must be "true" or empty, not "$(LOCAL_IS_HOST_MODULE)")
@@ -47,16 +46,8 @@ ifdef LOCAL_IS_HOST_MODULE
   my_host := host-
   my_kind := HOST
 else
-  ifdef LOCAL_IS_AUX_MODULE
-    ifneq ($(LOCAL_IS_AUX_MODULE),true)
-      $(error $(LOCAL_PATH): LOCAL_IS_AUX_MODULE must be "true" or empty, not "$(LOCAL_IS_AUX_MODULE)")
-    endif
-    my_prefix := AUX_
-    my_kind := AUX
-  else
-    my_prefix := TARGET_
-    my_kind :=
-  endif
+  my_prefix := TARGET_
+  my_kind :=
   my_host :=
 endif
 
@@ -316,12 +307,9 @@ else
   my_all_targets := device_$(my_register_name)_all_targets
 endif
 
-# variant is enough to make nano class unique; it serves as a key to lookup (OS,ARCH) tuple
-aux_class := $($(my_prefix)OS_VARIANT)
 # Make sure that this IS_HOST/CLASS/MODULE combination is unique.
 module_id := MODULE.$(if \
-    $(LOCAL_IS_HOST_MODULE),$($(my_prefix)OS),$(if \
-    $(LOCAL_IS_AUX_MODULE),$(aux_class),TARGET)).$(LOCAL_MODULE_CLASS).$(my_register_name)
+    $(LOCAL_IS_HOST_MODULE),$($(my_prefix)OS),TARGET).$(LOCAL_MODULE_CLASS).$(my_register_name)
 ifdef $(module_id)
 $(error $(LOCAL_PATH): $(module_id) already defined by $($(module_id)))
 endif
@@ -428,7 +416,6 @@ $(cleantarget)::
 ###########################################################
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_PATH:=$(LOCAL_PATH)
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_IS_HOST_MODULE := $(LOCAL_IS_HOST_MODULE)
-$(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_IS_AUX_MODULE := $(LOCAL_IS_AUX_MODULE)
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_HOST:= $(my_host)
 $(LOCAL_INTERMEDIATE_TARGETS) : PRIVATE_PREFIX := $(my_prefix)
 
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index 3d481df55..90bef1b77 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -474,17 +474,6 @@ LOCAL_ROBOTEST_FILES :=
 LOCAL_ROBOTEST_TIMEOUT :=
 LOCAL_TEST_PACKAGE :=
 
-# Aux specific variables
-LOCAL_AUX_ARCH :=
-LOCAL_AUX_CPU :=
-LOCAL_AUX_OS :=
-LOCAL_AUX_OS_VARIANT :=
-LOCAL_AUX_SUBARCH :=
-LOCAL_AUX_TOOLCHAIN :=
-LOCAL_CUSTOM_BUILD_STEP_INPUT:=
-LOCAL_CUSTOM_BUILD_STEP_OUTPUT:=
-LOCAL_IS_AUX_MODULE :=
-
 full_android_manifest :=
 non_system_module :=
 
diff --git a/core/config.mk b/core/config.mk
index f086a9aab..90bc8e70c 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -122,6 +122,18 @@ $(KATI_obsolete_var PRODUCT_IOT)
 $(KATI_obsolete_var MD5SUM)
 $(KATI_obsolete_var BOARD_HAL_STATIC_LIBRARIES, See $(CHANGES_URL)#BOARD_HAL_STATIC_LIBRARIES)
 $(KATI_obsolete_var LOCAL_HAL_STATIC_LIBRARIES, See $(CHANGES_URL)#BOARD_HAL_STATIC_LIBRARIES)
+$(KATI_obsolete_var \
+  TARGET_AUX_OS_VARIANT_LIST \
+  LOCAL_AUX_ARCH \
+  LOCAL_AUX_CPU \
+  LOCAL_AUX_OS \
+  LOCAL_AUX_OS_VARIANT \
+  LOCAL_AUX_SUBARCH \
+  LOCAL_AUX_TOOLCHAIN \
+  LOCAL_CUSTOM_BUILD_STEP_INPUT \
+  LOCAL_CUSTOM_BUILD_STEP_OUTPUT \
+  LOCAL_IS_AUX_MODULE \
+  ,AUX support has been removed)
 
 # Used to force goals to build.  Only use for conditionally defined goals.
 .PHONY: FORCE
@@ -170,8 +182,6 @@ BUILD_HOST_STATIC_LIBRARY :=$= $(BUILD_SYSTEM)/host_static_library.mk
 BUILD_HOST_SHARED_LIBRARY :=$= $(BUILD_SYSTEM)/host_shared_library.mk
 BUILD_STATIC_LIBRARY :=$= $(BUILD_SYSTEM)/static_library.mk
 BUILD_HEADER_LIBRARY :=$= $(BUILD_SYSTEM)/header_library.mk
-BUILD_AUX_STATIC_LIBRARY :=$= $(BUILD_SYSTEM)/aux_static_library.mk
-BUILD_AUX_EXECUTABLE :=$= $(BUILD_SYSTEM)/aux_executable.mk
 BUILD_SHARED_LIBRARY :=$= $(BUILD_SYSTEM)/shared_library.mk
 BUILD_EXECUTABLE :=$= $(BUILD_SYSTEM)/executable.mk
 BUILD_HOST_EXECUTABLE :=$= $(BUILD_SYSTEM)/host_executable.mk
diff --git a/core/config_sanitizers.mk b/core/config_sanitizers.mk
index 8c76a8d17..c5cb91c10 100644
--- a/core/config_sanitizers.mk
+++ b/core/config_sanitizers.mk
@@ -372,8 +372,8 @@ ifneq ($(filter hwaddress,$(my_sanitize)),)
   my_cflags += $(HWADDRESS_SANITIZER_CONFIG_EXTRA_CFLAGS)
 endif
 
-# Use minimal diagnostics when integer overflow is enabled; never do it for HOST or AUX modules
-ifeq ($(LOCAL_IS_HOST_MODULE)$(LOCAL_IS_AUX_MODULE),)
+# Use minimal diagnostics when integer overflow is enabled; never do it for HOST modules
+ifeq ($(LOCAL_IS_HOST_MODULE),)
   # Pre-emptively add UBSAN minimal runtime incase a static library dependency requires it
   ifeq ($(filter STATIC_LIBRARIES,$(LOCAL_MODULE_CLASS)),)
     ifndef LOCAL_SDK_VERSION
diff --git a/core/definitions.mk b/core/definitions.mk
index 6d8cddb3d..1467e9687 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -95,7 +95,6 @@ ANDROID_RESOURCE_GENERATED_CLASSES := 'R.class' 'R$$*.class' 'Manifest.class' 'M
 
 # Display names for various build targets
 TARGET_DISPLAY := target
-AUX_DISPLAY := aux
 HOST_DISPLAY := host
 HOST_CROSS_DISPLAY := host cross
 
@@ -510,23 +509,18 @@ define reverse-list
 $(if $(1),$(call reverse-list,$(wordlist 2,$(words $(1)),$(1)))) $(firstword $(1))
 endef
 
-define def-host-aux-target
-$(eval _idf_val_:=$(if $(strip $(LOCAL_IS_HOST_MODULE)),HOST,$(if $(strip $(LOCAL_IS_AUX_MODULE)),AUX,))) \
-$(_idf_val_)
-endef
-
 ###########################################################
 ## Returns correct _idfPrefix from the list:
-##   { HOST, HOST_CROSS, AUX, TARGET }
+##   { HOST, HOST_CROSS, TARGET }
 ###########################################################
 # the following rules checked in order:
-# ($1 is in {AUX, HOST_CROSS} => $1;
+# ($1 is in {HOST_CROSS} => $1;
 # ($1 is empty) => TARGET;
 # ($2 is not empty) => HOST_CROSS;
 # => HOST;
 define find-idf-prefix
 $(strip \
-    $(eval _idf_pfx_:=$(strip $(filter AUX HOST_CROSS,$(1)))) \
+    $(eval _idf_pfx_:=$(strip $(filter HOST_CROSS,$(1)))) \
     $(eval _idf_pfx_:=$(if $(strip $(1)),$(if $(_idf_pfx_),$(_idf_pfx_),$(if $(strip $(2)),HOST_CROSS,HOST)),TARGET)) \
     $(_idf_pfx_)
 )
@@ -542,7 +536,7 @@ endef
 
 # $(1): target class, like "APPS"
 # $(2): target name, like "NotePad"
-# $(3): { HOST, HOST_CROSS, AUX, <empty (TARGET)>, <other non-empty (HOST)> }
+# $(3): { HOST, HOST_CROSS, <empty (TARGET)>, <other non-empty (HOST)> }
 # $(4): if non-empty, force the intermediates to be COMMON
 # $(5): if non-empty, force the intermediates to be for the 2nd arch
 # $(6): if non-empty, force the intermediates to be for the host cross os
@@ -579,7 +573,7 @@ $(strip \
         $(error $(LOCAL_PATH): LOCAL_MODULE_CLASS not defined before call to local-intermediates-dir)) \
     $(if $(strip $(LOCAL_MODULE)),, \
         $(error $(LOCAL_PATH): LOCAL_MODULE not defined before call to local-intermediates-dir)) \
-    $(call intermediates-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(call def-host-aux-target),$(1),$(2),$(3)) \
+    $(call intermediates-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(if $(strip $(LOCAL_IS_HOST_MODULE)),HOST),$(1),$(2),$(3)) \
 )
 endef
 
@@ -594,7 +588,7 @@ endef
 
 # $(1): target class, like "APPS"
 # $(2): target name, like "NotePad"
-# $(3): { HOST, HOST_CROSS, AUX, <empty (TARGET)>, <other non-empty (HOST)> }
+# $(3): { HOST, HOST_CROSS, <empty (TARGET)>, <other non-empty (HOST)> }
 # $(4): if non-empty, force the generated sources to be COMMON
 define generated-sources-dir-for
 $(strip \
@@ -624,7 +618,7 @@ $(strip \
         $(error $(LOCAL_PATH): LOCAL_MODULE_CLASS not defined before call to local-generated-sources-dir)) \
     $(if $(strip $(LOCAL_MODULE)),, \
         $(error $(LOCAL_PATH): LOCAL_MODULE not defined before call to local-generated-sources-dir)) \
-    $(call generated-sources-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(call def-host-aux-target),$(1)) \
+    $(call generated-sources-dir-for,$(LOCAL_MODULE_CLASS),$(LOCAL_MODULE),$(if $(strip $(LOCAL_IS_HOST_MODULE)),HOST),$(1)) \
 )
 endef
 
@@ -1499,89 +1493,6 @@ $(call split-long-arguments,$($(PRIVATE_2ND_ARCH_VAR_PREFIX)TARGET_AR) \
 $(hide) mv -f $@.tmp $@
 endef
 
-# $(1): the full path of the source static library.
-# $(2): the full path of the destination static library.
-define _extract-and-include-single-aux-whole-static-lib
-$(hide) ldir=$(PRIVATE_INTERMEDIATES_DIR)/WHOLE/$(basename $(notdir $(1)))_objs;\
-    rm -rf $$ldir; \
-    mkdir -p $$ldir; \
-    cp $(1) $$ldir; \
-    lib_to_include=$$ldir/$(notdir $(1)); \
-    filelist=; \
-    subdir=0; \
-    for f in `$(PRIVATE_AR) t $(1)`; do \
-        if [ -e $$ldir/$$f ]; then \
-            mkdir $$ldir/$$subdir; \
-            ext=$$subdir/; \
-            subdir=$$((subdir+1)); \
-            $(PRIVATE_AR) m $$lib_to_include $$f; \
-        else \
-            ext=; \
-        fi; \
-        $(PRIVATE_AR) p $$lib_to_include $$f > $$ldir/$$ext$$f; \
-        filelist="$$filelist $$ldir/$$ext$$f"; \
-    done ; \
-    $(PRIVATE_AR) $(AUX_GLOBAL_ARFLAGS) $(2) $$filelist
-
-endef
-
-define extract-and-include-aux-whole-static-libs
-$(call extract-and-include-whole-static-libs-first, $(firstword $(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)),$(1))
-$(foreach lib,$(wordlist 2,999,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)), \
-    $(call _extract-and-include-single-aux-whole-static-lib, $(lib), $(1)))
-endef
-
-# Explicitly delete the archive first so that ar doesn't
-# try to add to an existing archive.
-define transform-o-to-aux-static-lib
-@echo "$($(PRIVATE_PREFIX)DISPLAY) StaticLib: $(PRIVATE_MODULE) ($@)"
-@mkdir -p $(dir $@)
-@rm -f $@ $@.tmp
-$(call extract-and-include-aux-whole-static-libs,$@.tmp)
-$(call split-long-arguments,$(PRIVATE_AR) \
-    $(AUX_GLOBAL_ARFLAGS) $@.tmp,$(PRIVATE_ALL_OBJECTS))
-$(hide) mv -f $@.tmp $@
-endef
-
-define transform-o-to-aux-executable-inner
-$(hide) $(PRIVATE_CXX_LINK) -pie \
-  -Bdynamic \
-  -Wl,--gc-sections \
-  $(PRIVATE_ALL_OBJECTS) \
-  -Wl,--whole-archive \
-  $(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES) \
-  -Wl,--no-whole-archive \
-  $(PRIVATE_ALL_STATIC_LIBRARIES) \
-  $(PRIVATE_LDFLAGS) \
-  -o $@
-endef
-
-define transform-o-to-aux-executable
-@echo "$(AUX_DISPLAY) Executable: $(PRIVATE_MODULE) ($@)"
-@mkdir -p $(dir $@)
-$(transform-o-to-aux-executable-inner)
-endef
-
-define transform-o-to-aux-static-executable-inner
-$(hide) $(PRIVATE_CXX_LINK) \
-  -Bstatic \
-  -Wl,--gc-sections \
-  $(PRIVATE_ALL_OBJECTS) \
-  -Wl,--whole-archive \
-  $(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES) \
-  -Wl,--no-whole-archive \
-  $(PRIVATE_ALL_STATIC_LIBRARIES) \
-  $(PRIVATE_LDFLAGS) \
-  -Wl,-Map=$(@).map \
-  -o $@
-endef
-
-define transform-o-to-aux-static-executable
-@echo "$(AUX_DISPLAY) StaticExecutable: $(PRIVATE_MODULE) ($@)"
-@mkdir -p $(dir $@)
-$(transform-o-to-aux-static-executable-inner)
-endef
-
 ###########################################################
 ## Commands for running host ar
 ###########################################################
diff --git a/core/deprecation.mk b/core/deprecation.mk
index 19bd4cfb9..879505b37 100644
--- a/core/deprecation.mk
+++ b/core/deprecation.mk
@@ -29,8 +29,6 @@ DEFAULT_WARNING_BUILD_MODULE_TYPES :=$= \
 # BUILD_BROKEN_USES_BUILD_* in your BoardConfig.mk in order to turn them back
 # to warnings.
 DEFAULT_ERROR_BUILD_MODULE_TYPES :=$= \
-  BUILD_AUX_EXECUTABLE \
-  BUILD_AUX_STATIC_LIBRARY \
   BUILD_COPY_HEADERS \
   BUILD_HOST_EXECUTABLE \
   BUILD_HOST_FUZZ_TEST \
@@ -46,6 +44,8 @@ DEFAULT_ERROR_BUILD_MODULE_TYPES :=$= \
 # These are BUILD_* variables that are always errors to reference.
 # Setting the BUILD_BROKEN_USES_BUILD_* variables is also an error.
 OBSOLETE_BUILD_MODULE_TYPES :=$= \
+  BUILD_AUX_EXECUTABLE \
+  BUILD_AUX_STATIC_LIBRARY \
   BUILD_HOST_SHARED_TEST_LIBRARY \
   BUILD_SHARED_TEST_LIBRARY \
 
diff --git a/core/envsetup.mk b/core/envsetup.mk
index ac3d5cff9..109385684 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -360,9 +360,6 @@ HOST_OUT_FAKE := $(HOST_OUT)/fake_packages
   HOST_OUT_COMMON_INTERMEDIATES \
   HOST_OUT_FAKE
 
-# Nano environment config
-include $(BUILD_SYSTEM)/aux_config.mk
-
 HOST_CROSS_OUT_INTERMEDIATES := $(HOST_CROSS_OUT)/obj
 HOST_CROSS_OUT_NOTICE_FILES := $(HOST_CROSS_OUT_INTERMEDIATES)/NOTICE_FILES
 .KATI_READONLY := \
diff --git a/core/link_type.mk b/core/link_type.mk
index f7604ff4a..ff525cb04 100644
--- a/core/link_type.mk
+++ b/core/link_type.mk
@@ -10,7 +10,7 @@
 #   my_link_deps: the dependencies, in the form of <MODULE_CLASS>:<name>
 #
 
-my_link_prefix := LINK_TYPE:$(call find-idf-prefix,$(my_kind),$(my_host_cross))$(if $(filter AUX,$(my_kind)),-$(AUX_OS_VARIANT)):$(if $(my_common),$(my_common):_,_:$(if $(my_2nd_arch_prefix),$(my_2nd_arch_prefix),_))
+my_link_prefix := LINK_TYPE:$(call find-idf-prefix,$(my_kind),$(my_host_cross)):$(if $(my_common),$(my_common):_,_:$(if $(my_2nd_arch_prefix),$(my_2nd_arch_prefix),_))
 link_type := $(my_link_prefix):$(LOCAL_MODULE_CLASS):$(LOCAL_MODULE)
 ALL_LINK_TYPES := $(ALL_LINK_TYPES) $(link_type)
 $(link_type).TYPE := $(my_link_type)
diff --git a/core/main.mk b/core/main.mk
index 8b8517036..151a01831 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -344,9 +344,6 @@ ifneq ($(words $(sort $(filter-out $(INTERNAL_MODIFIER_TARGETS) checkbuild emula
 $(error The 'sdk' target may not be specified with any other targets)
 endif
 
-# AUX dependencies are already added by now; remove triggers from the MAKECMDGOALS
-MAKECMDGOALS := $(strip $(filter-out AUX-%,$(MAKECMDGOALS)))
-
 # TODO: this should be eng I think.  Since the sdk is built from the eng
 # variant.
 tags_to_install := debug eng
@@ -830,7 +827,6 @@ add-required-deps :=
 #     - TARGET
 #     - HOST
 #     - HOST_CROSS
-#     - AUX-<variant-name>
 #   3: Whether to use the common intermediates directory or not
 #     - _
 #     - COMMON
@@ -857,14 +853,8 @@ add-required-deps :=
 
 link_type_error :=
 
-define link-type-prefix-base
-$(word 2,$(subst :,$(space),$(1)))
-endef
 define link-type-prefix
-$(if $(filter AUX-%,$(link-type-prefix-base)),$(patsubst AUX-%,AUX,$(link-type-prefix-base)),$(link-type-prefix-base))
-endef
-define link-type-aux-variant
-$(if $(filter AUX-%,$(link-type-prefix-base)),$(patsubst AUX-%,%,$(link-type-prefix-base)))
+$(word 2,$(subst :,$(space),$(1)))
 endef
 define link-type-common
 $(patsubst _,,$(word 3,$(subst :,$(space),$(1))))
@@ -882,7 +872,7 @@ define link-type-os
 $(strip $(eval _p := $(link-type-prefix))\
   $(if $(filter HOST HOST_CROSS,$(_p)),\
     $($(_p)_OS),\
-    $(if $(filter AUX,$(_p)),AUX,android)))
+    android))
 endef
 define link-type-arch
 $($(link-type-prefix)_$(link-type-2ndarchprefix)ARCH)
@@ -1435,9 +1425,6 @@ bootimage_test_harness: $(INSTALLED_TEST_HARNESS_BOOTIMAGE_TARGET)
 .PHONY: vbmetaimage
 vbmetaimage: $(INSTALLED_VBMETAIMAGE_TARGET)
 
-.PHONY: auxiliary
-auxiliary: $(INSTALLED_AUX_TARGETS)
-
 # Build files and then package it into the rom formats
 .PHONY: droidcore
 droidcore: $(filter $(HOST_OUT_ROOT)/%,$(modules_to_install)) \
@@ -1483,7 +1470,6 @@ droidcore: $(filter $(HOST_OUT_ROOT)/%,$(modules_to_install)) \
     $(INSTALLED_FILES_FILE_RECOVERY) \
     $(INSTALLED_FILES_JSON_RECOVERY) \
     $(INSTALLED_ANDROID_INFO_TXT_TARGET) \
-    auxiliary \
     soong_docs
 
 # dist_files only for putting your library into the dist directory with a full build.
diff --git a/core/ninja_config.mk b/core/ninja_config.mk
index 3f2e5de8e..1ead512a8 100644
--- a/core/ninja_config.mk
+++ b/core/ninja_config.mk
@@ -15,7 +15,6 @@ PARSE_TIME_MAKE_GOALS := \
 	$(dont_bother_goals) \
 	all \
 	ECLIPSE-% \
-	AUX-% \
 	brillo_tests \
 	btnod \
 	build-art% \