diff --git a/core/Makefile b/core/Makefile
index 9dfdcd0..f6b0401 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -363,6 +363,10 @@
 )
 INTERNAL_VENDOR_RAMDISK_FRAGMENTS += $(BOARD_VENDOR_RAMDISK_FRAGMENTS)
 
+ifneq ($(BOARD_KERNEL_MODULES_16K),)
+INTERNAL_VENDOR_RAMDISK_FRAGMENTS += 16K
+endif
+
 # Strip the list in case of any whitespace.
 INTERNAL_VENDOR_RAMDISK_FRAGMENTS := \
   $(strip $(INTERNAL_VENDOR_RAMDISK_FRAGMENTS))
@@ -1050,16 +1054,32 @@
 BUILT_RAMDISK_16K_TARGET := $(PRODUCT_OUT)/ramdisk_16k.img
 RAMDISK_16K_STAGING_DIR := $(call intermediates-dir-for,PACKAGING,depmod_ramdisk_16k)
 
-$(BUILT_RAMDISK_16K_TARGET): $(DEPMOD) $(MKBOOTFS)
-$(BUILT_RAMDISK_16K_TARGET): $(call copy-many-files,$(foreach file,$(BOARD_KERNEL_MODULES_16K),$(file):$(RAMDISK_16K_STAGING_DIR)/lib/modules/0.0/$(notdir $(file))))
+$(foreach \
+  file,\
+  $(BOARD_KERNEL_MODULES_16K),\
+  $(eval \
+    $(call copy-and-strip-kernel-module,\
+      $(file),\
+      $(RAMDISK_16K_STAGING_DIR)/lib/modules/0.0/$(notdir $(file)) \
+    ) \
+  ) \
+)
+
+BOARD_VENDOR_RAMDISK_FRAGMENT.16K.PREBUILT := $(BUILT_RAMDISK_16K_TARGET)
+
+$(BUILT_RAMDISK_16K_TARGET): $(DEPMOD) $(MKBOOTFS) $(EXTRACT_KERNEL) $(COMPRESSION_COMMAND_DEPS)
+$(BUILT_RAMDISK_16K_TARGET): $(foreach file,$(BOARD_KERNEL_MODULES_16K),$(RAMDISK_16K_STAGING_DIR)/lib/modules/0.0/$(notdir $(file)))
 	$(DEPMOD) -b $(RAMDISK_16K_STAGING_DIR) 0.0
 	for MODULE in $(BOARD_KERNEL_MODULES_16K); do \
 		basename $$MODULE >> $(RAMDISK_16K_STAGING_DIR)/lib/modules/0.0/modules.load ; \
 	done;
-	mkdir -p $(TARGET_OUT_RAMDISK_16K)/lib
 	rm -rf $(TARGET_OUT_RAMDISK_16K)/lib/modules
-	cp -r $(RAMDISK_16K_STAGING_DIR)/lib/modules/0.0 $(TARGET_OUT_RAMDISK_16K)/lib/modules
-	$(MKBOOTFS) $(TARGET_OUT_RAMDISK_16K) > $@
+	mkdir -p $(TARGET_OUT_RAMDISK_16K)/lib/modules
+	KERNEL_RELEASE=`$(EXTRACT_KERNEL) --tools lz4:$(LZ4) --input $(BOARD_KERNEL_PATH_16K) --output-release` ;\
+	IS_16K_KERNEL=`$(EXTRACT_KERNEL) --tools lz4:$(LZ4) --input $(BOARD_KERNEL_PATH_16K) --output-config` ;\
+	if [[ "$$IS_16K_KERNEL" == *"CONFIG_ARM64_16K_PAGES=y"* ]]; then SUFFIX=_16k; fi ;\
+	cp -r $(RAMDISK_16K_STAGING_DIR)/lib/modules/0.0 $(TARGET_OUT_RAMDISK_16K)/lib/modules/$$KERNEL_RELEASE$$SUFFIX
+	$(MKBOOTFS) $(TARGET_OUT_RAMDISK_16K) | $(COMPRESSION_COMMAND) > $@
 
 # Builds a ramdisk using modules defined in BOARD_KERNEL_MODULES_16K
 ramdisk_16k: $(BUILT_RAMDISK_16K_TARGET)
@@ -1076,6 +1096,23 @@
 kernel_16k: $(BUILT_KERNEL_16K_TARGET)
 .PHONY: kernel_16k
 
+BUILT_BOOTIMAGE_16K_TARGET := $(PRODUCT_OUT)/boot_16k.img
+
+$(BUILT_BOOTIMAGE_16K_TARGET): $(MKBOOTIMG) $(AVBTOOL) $(INTERNAL_BOOTIMAGE_FILES) $(BOARD_AVB_BOOT_KEY_PATH) $(INTERNAL_GKI_CERTIFICATE_DEPS)
+	$(call pretty,"Target boot 16k image: $@")
+	$(call build_boot_from_kernel_avb_enabled,$@,$(BUILT_KERNEL_16K_TARGET))
+
+
+bootimage_16k: $(BUILT_BOOTIMAGE_16K_TARGET)
+.PHONY: bootimage_16k
+
+BUILT_BOOT_OTA_PACKAGE_16K := $(PRODUCT_OUT)/boot_ota_16k.zip
+$(BUILT_BOOT_OTA_PACKAGE_16K): $(OTA_FROM_RAW_IMG) $(BUILT_BOOTIMAGE_16K_TARGET)
+	$(OTA_FROM_RAW_IMG) --path $(HOST_OUT) --partition_name boot --output $@ $(BUILT_BOOTIMAGE_16K_TARGET)
+
+boototapackage_16k: $(BUILT_BOOT_OTA_PACKAGE_16K)
+.PHONY: boototapackage_16k
+
 endif
 
 
@@ -1171,6 +1208,29 @@
   $(if $(1),--partition_size $(1),--dynamic_partition_size)
 endef
 
+# $1: output boot image target
+# $2: input path to kernel binary
+define build_boot_from_kernel_avb_enabled
+  $(eval kernel := $(2))
+  $(MKBOOTIMG) --kernel $(kernel) $(INTERNAL_BOOTIMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(1)
+  $(if $(BOARD_GKI_SIGNING_KEY_PATH), \
+    $(eval boot_signature := $(call intermediates-dir-for,PACKAGING,generic_boot)/$(notdir $(1)).boot_signature) \
+    $(eval kernel_signature := $(call intermediates-dir-for,PACKAGING,generic_kernel)/$(notdir $(kernel)).boot_signature) \
+    $(call generate_generic_boot_image_certificate,$(1),$(boot_signature),boot,$(BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS)) $(newline) \
+    $(call generate_generic_boot_image_certificate,$(kernel),$(kernel_signature),generic_kernel,$(BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS)) $(newline) \
+    cat $(kernel_signature) >> $(boot_signature) $(newline) \
+    $(call assert-max-image-size,$(boot_signature),16 << 10) $(newline) \
+    truncate -s $$(( 16 << 10 )) $(boot_signature) $(newline) \
+    cat "$(boot_signature)" >> $(1))
+  $(call assert-max-image-size,$(1),$(call get-hash-image-max-size,$(call get-bootimage-partition-size,$(1),boot)))
+  $(AVBTOOL) add_hash_footer \
+          --image $(1) \
+          $(call get-partition-size-argument,$(call get-bootimage-partition-size,$(1),boot)) \
+          --partition_name boot $(INTERNAL_AVB_BOOT_SIGNING_ARGS) \
+          $(BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS)
+endef
+
+
 ifndef BOARD_PREBUILT_BOOTIMAGE
 
 ifneq ($(strip $(TARGET_NO_KERNEL)),true)
@@ -1275,22 +1335,7 @@
 # $1: boot image target
 define build_boot_board_avb_enabled
   $(eval kernel := $(call bootimage-to-kernel,$(1)))
-  $(MKBOOTIMG) --kernel $(kernel) $(INTERNAL_BOOTIMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(1)
-  $(if $(BOARD_GKI_SIGNING_KEY_PATH), \
-    $(eval boot_signature := $(call intermediates-dir-for,PACKAGING,generic_boot)/$(notdir $(1)).boot_signature) \
-    $(eval kernel_signature := $(call intermediates-dir-for,PACKAGING,generic_kernel)/$(notdir $(kernel)).boot_signature) \
-    $(call generate_generic_boot_image_certificate,$(1),$(boot_signature),boot,$(BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS)) $(newline) \
-    $(call generate_generic_boot_image_certificate,$(kernel),$(kernel_signature),generic_kernel,$(BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS)) $(newline) \
-    cat $(kernel_signature) >> $(boot_signature) $(newline) \
-    $(call assert-max-image-size,$(boot_signature),16 << 10) $(newline) \
-    truncate -s $$(( 16 << 10 )) $(boot_signature) $(newline) \
-    cat "$(boot_signature)" >> $(1))
-  $(call assert-max-image-size,$(1),$(call get-hash-image-max-size,$(call get-bootimage-partition-size,$(1),boot)))
-  $(AVBTOOL) add_hash_footer \
-          --image $(1) \
-          $(call get-partition-size-argument,$(call get-bootimage-partition-size,$(1),boot)) \
-          --partition_name boot $(INTERNAL_AVB_BOOT_SIGNING_ARGS) \
-          $(BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS)
+  $(call build_boot_from_kernel_avb_enabled,$(1),$(kernel))
 endef
 
 $(INSTALLED_BOOTIMAGE_TARGET): $(MKBOOTIMG) $(AVBTOOL) $(INTERNAL_BOOTIMAGE_FILES) $(BOARD_AVB_BOOT_KEY_PATH) $(INTERNAL_GKI_CERTIFICATE_DEPS)
@@ -5730,9 +5775,6 @@
 ifeq ($(BUILDING_WITH_VSDK),true)
 	$(hide) echo "building_with_vsdk=true" >> $@
 endif
-ifeq ($(TARGET_FLATTEN_APEX),false)
-	$(hide) echo "target_flatten_apex=false" >> $@
-endif
 
 $(call declare-0p-target,$(INSTALLED_FASTBOOT_INFO_TARGET))
 
diff --git a/core/base_rules.mk b/core/base_rules.mk
index e7c28ec..b3c5b94 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -965,6 +965,9 @@
       $(my_init_rc_installed) \
       $(my_installed_test_data) \
       $(my_vintf_installed))
+
+  ALL_MODULES.$(my_register_name).INSTALLED_SYMLINKS := $(LOCAL_SOONG_INSTALL_SYMLINKS)
+
   # Store the list of colon-separated pairs of the built and installed locations
   # of files provided by this module.  Used by custom packaging rules like
   # package-modules.mk that need to copy the built files to a custom install
diff --git a/core/board_config.mk b/core/board_config.mk
index c3a6864..2699512 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -971,24 +971,6 @@
 endif
 TARGET_VENDOR_TEST_SUFFIX := /vendor
 
-###########################################
-# APEXes are by default not flattened, i.e. updatable.
-#
-# 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 := $(OVERRIDE_TARGET_FLATTEN_APEX)
-endif
-
-# TODO(b/278826656) Remove the following message
-ifeq (true,$(TARGET_FLATTEN_APEX))
-  $(warning ********************************************************************************)
-  $(warning Flattened APEX will be deprecated soon. Please stop using flattened APEX and use)
-  $(warning "image" APEX instead.)
-  $(warning ********************************************************************************)
-endif
-
 ifeq (,$(TARGET_BUILD_UNBUNDLED))
 ifdef PRODUCT_EXTRA_VNDK_VERSIONS
   $(foreach v,$(PRODUCT_EXTRA_VNDK_VERSIONS),$(call check_vndk_version,$(v)))
diff --git a/core/config.mk b/core/config.mk
index 2a30dd9..ac49cec 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -408,22 +408,6 @@
 $(if $(findstring ro.config.low_ram=true,$(PRODUCT_ODM_PROPERTIES)),true,false)))))))))
 endef
 
-# Get the board API level.
-board_api_level := $(PLATFORM_SDK_VERSION)
-ifdef BOARD_API_LEVEL
-  board_api_level := $(BOARD_API_LEVEL)
-else ifdef BOARD_SHIPPING_API_LEVEL
-  # Vendors with GRF must define BOARD_SHIPPING_API_LEVEL for the vendor API level.
-  board_api_level := $(BOARD_SHIPPING_API_LEVEL)
-endif
-
-# Calculate the VSR vendor API level.
-vsr_vendor_api_level := $(board_api_level)
-
-ifdef PRODUCT_SHIPPING_API_LEVEL
-  vsr_vendor_api_level := $(call math_min,$(PRODUCT_SHIPPING_API_LEVEL),$(board_api_level))
-endif
-
 # Set TARGET_MAX_PAGE_SIZE_SUPPORTED.
 # TARGET_MAX_PAGE_SIZE_SUPPORTED indicates the alignment of the ELF segments.
 ifdef PRODUCT_MAX_PAGE_SIZE_SUPPORTED
@@ -435,7 +419,7 @@
   # The default binary alignment for userspace is 4096.
   TARGET_MAX_PAGE_SIZE_SUPPORTED := 4096
   # When VSR vendor API level >= 34, binary alignment will be 65536.
-  ifeq ($(call math_gt_or_eq,$(vsr_vendor_api_level),34),true)
+  ifeq ($(call math_gt_or_eq,$(VSR_VENDOR_API_LEVEL),34),true)
     ifeq ($(TARGET_ARCH),arm64)
       TARGET_MAX_PAGE_SIZE_SUPPORTED := 65536
     endif
@@ -740,6 +724,7 @@
 IMG_FROM_TARGET_FILES := $(HOST_OUT_EXECUTABLES)/img_from_target_files$(HOST_EXECUTABLE_SUFFIX)
 MAKE_RECOVERY_PATCH := $(HOST_OUT_EXECUTABLES)/make_recovery_patch$(HOST_EXECUTABLE_SUFFIX)
 OTA_FROM_TARGET_FILES := $(HOST_OUT_EXECUTABLES)/ota_from_target_files$(HOST_EXECUTABLE_SUFFIX)
+OTA_FROM_RAW_IMG := $(HOST_OUT_EXECUTABLES)/ota_from_raw_img$(HOST_EXECUTABLE_SUFFIX)
 SPARSE_IMG := $(HOST_OUT_EXECUTABLES)/sparse_img$(HOST_EXECUTABLE_SUFFIX)
 CHECK_PARTITION_SIZES := $(HOST_OUT_EXECUTABLES)/check_partition_sizes$(HOST_EXECUTABLE_SUFFIX)
 SYMBOLS_MAP := $(HOST_OUT_EXECUTABLES)/symbols_map
@@ -945,13 +930,14 @@
 .KATI_READONLY := IS_TARGET_MIXED_SEPOLICY
 
 # A list of SEPolicy versions, besides PLATFORM_SEPOLICY_VERSION, that the framework supports.
-PLATFORM_SEPOLICY_COMPAT_VERSIONS := \
+PLATFORM_SEPOLICY_COMPAT_VERSIONS := $(filter-out $(PLATFORM_SEPOLICY_VERSION), \
     29.0 \
     30.0 \
     31.0 \
     32.0 \
     33.0 \
     34.0 \
+    )
 
 .KATI_READONLY := \
     PLATFORM_SEPOLICY_COMPAT_VERSIONS \
diff --git a/core/dex_preopt_odex_install.mk b/core/dex_preopt_odex_install.mk
index 288f81f..af6d921 100644
--- a/core/dex_preopt_odex_install.mk
+++ b/core/dex_preopt_odex_install.mk
@@ -468,8 +468,6 @@
 	rsync --checksum $(PRIVATE_STAGING) $@
 
   my_dexpreopt_script := $(intermediates)/dexpreopt.sh
-  my_dexpreopt_zip := $(intermediates)/dexpreopt.zip
-  DEXPREOPT.$(LOCAL_MODULE).POST_INSTALLED_DEXPREOPT_ZIP := $(my_dexpreopt_zip)
   .KATI_RESTAT: $(my_dexpreopt_script)
   $(my_dexpreopt_script): PRIVATE_MODULE := $(LOCAL_MODULE)
   $(my_dexpreopt_script): PRIVATE_GLOBAL_SOONG_CONFIG := $(DEX_PREOPT_SOONG_CONFIG_FOR_MAKE)
@@ -499,38 +497,67 @@
     my_dexpreopt_deps += $(intermediates)/enforce_uses_libraries.status
   endif
 
+  # We need to add all the installed files to ALL_MODULES.$(my_register_name).INSTALLED in order
+  # for the build system to properly track installed files. (for sbom, installclean, etc)
+  # We install all the files in a zip file generated at execution time, which means we have to guess
+  # what's going to be in that zip file before it's created. We then check at executation time that
+  # our guess is correct.
+  # _system_other corresponds to OdexOnSystemOtherByName() in soong.
+  # The other paths correspond to dexpreoptCommand()
+  _dexlocation := $(patsubst $(PRODUCT_OUT)/%,%,$(LOCAL_INSTALLED_MODULE))
+  _dexname := $(basename $(notdir $(_dexlocation)))
+  _system_other := $(strip $(if $(strip $(BOARD_USES_SYSTEM_OTHER_ODEX)), \
+    $(if $(strip $(SANITIZE_LITE)),, \
+      $(if $(filter $(_dexname),$(PRODUCT_DEXPREOPT_SPEED_APPS))$(filter $(_dexname),$(PRODUCT_SYSTEM_SERVER_APPS)),, \
+        $(if $(strip $(foreach myfilter,$(SYSTEM_OTHER_ODEX_FILTER),$(filter system/$(myfilter),$(_dexlocation)))), \
+          system_other/)))))
+  # _dexdir has a trailing /
+  _dexdir := $(_system_other)$(dir $(_dexlocation))
+  my_dexpreopt_zip_contents := $(sort \
+    $(foreach arch,$(my_dexpreopt_archs), \
+      $(_dexdir)oat/$(arch)/$(_dexname).odex \
+      $(_dexdir)oat/$(arch)/$(_dexname).vdex \
+      $(if $(filter false,$(LOCAL_DEX_PREOPT_APP_IMAGE)),, \
+        $(if $(my_process_profile)$(filter true,$(LOCAL_DEX_PREOPT_APP_IMAGE)), \
+          $(_dexdir)oat/$(arch)/$(_dexname).art))) \
+    $(if $(my_process_profile),$(_dexlocation).prof))
+  _dexlocation :=
+  _dexdir :=
+  _dexname :=
+  _system_other :=
+
+  my_dexpreopt_zip := $(intermediates)/dexpreopt.zip
+  DEXPREOPT.$(LOCAL_MODULE).POST_INSTALLED_DEXPREOPT_ZIP := $(my_dexpreopt_zip)
   $(my_dexpreopt_zip): PRIVATE_MODULE := $(LOCAL_MODULE)
   $(my_dexpreopt_zip): $(my_dexpreopt_deps)
   $(my_dexpreopt_zip): | $(DEXPREOPT_GEN_DEPS)
   $(my_dexpreopt_zip): .KATI_DEPFILE := $(my_dexpreopt_zip).d
   $(my_dexpreopt_zip): PRIVATE_DEX := $(my_dex_jar)
   $(my_dexpreopt_zip): PRIVATE_SCRIPT := $(my_dexpreopt_script)
+  $(my_dexpreopt_zip): PRIVATE_ZIP_CONTENTS := $(my_dexpreopt_zip_contents)
   $(my_dexpreopt_zip): $(my_dexpreopt_script)
 	@echo "$(PRIVATE_MODULE) dexpreopt"
+	rm -f $@
+	echo -n > $@.contents
+	$(foreach f,$(PRIVATE_ZIP_CONTENTS),echo "$(f)" >> $@.contents$(newline))
 	bash $(PRIVATE_SCRIPT) $(PRIVATE_DEX) $@
+	if ! diff <(zipinfo -1 $@ | sort) $@.contents >&2; then \
+	  echo "Contents of $@ did not match what make was expecting." >&2 && exit 1; \
+	fi
 
-  ifdef LOCAL_POST_INSTALL_CMD
-    # Add a shell command separator
-    LOCAL_POST_INSTALL_CMD += &&
-  endif
+  $(foreach installed_dex_file,$(my_dexpreopt_zip_contents),\
+    $(eval $(PRODUCT_OUT)/$(installed_dex_file): $(my_dexpreopt_zip) \
+$(newline)	unzip -qoDD -d $(PRODUCT_OUT) $(my_dexpreopt_zip) $(installed_dex_file)))
 
-  LOCAL_POST_INSTALL_CMD += \
-    for i in $$(zipinfo -1 $(my_dexpreopt_zip)); \
-      do mkdir -p $(PRODUCT_OUT)/$$(dirname $$i); \
-    done && \
-    ( unzip -qoDD -d $(PRODUCT_OUT) $(my_dexpreopt_zip) 2>&1 | grep -v "zipfile is empty"; exit $${PIPESTATUS[0]} ) || \
-      ( code=$$?; if [ $$code -ne 0 -a $$code -ne 1 ]; then exit $$code; fi )
-
-  $(LOCAL_INSTALLED_MODULE): PRIVATE_POST_INSTALL_CMD := $(LOCAL_POST_INSTALL_CMD)
-  $(LOCAL_INSTALLED_MODULE): $(my_dexpreopt_zip)
-
-  $(my_all_targets): $(my_dexpreopt_zip)
+  ALL_MODULES.$(my_register_name).INSTALLED += $(addprefix $(PRODUCT_OUT)/,$(my_dexpreopt_zip_contents))
 
   my_dexpreopt_config :=
+  my_dexpreopt_config_for_postprocessing :=
+  my_dexpreopt_jar_copy :=
   my_dexpreopt_product_packages :=
   my_dexpreopt_script :=
   my_dexpreopt_zip :=
-  my_dexpreopt_config_for_postprocessing :=
+  my_dexpreopt_zip_contents :=
 endif # LOCAL_DEX_PREOPT
 endif # my_create_dexpreopt_config
 
diff --git a/core/main.mk b/core/main.mk
index 5738cdb..12b7bd0 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1720,8 +1720,10 @@
     unbundled_build_modules := $(sort $(TARGET_BUILD_APPS))
   endif
 
-  # Dist the installed files if they exist.
-  apps_only_installed_files := $(foreach m,$(unbundled_build_modules),$(ALL_MODULES.$(m).INSTALLED))
+  # Dist the installed files if they exist, except the installed symlinks. dist-for-goals emits
+  # `cp src dest` commands, which will fail to copy dangling symlinks.
+  apps_only_installed_files := $(foreach m,$(unbundled_build_modules),\
+    $(filter-out $(ALL_MODULES.$(m).INSTALLED_SYMLINKS),$(ALL_MODULES.$(m).INSTALLED)))
   $(call dist-for-goals,apps_only, $(apps_only_installed_files))
 
   # Dist the bundle files if they exist.
diff --git a/core/packaging/flags.mk b/core/packaging/flags.mk
index cb43741..697fe24 100644
--- a/core/packaging/flags.mk
+++ b/core/packaging/flags.mk
@@ -75,7 +75,7 @@
 define generate-partition-aconfig-flag-file
 $(eval $(strip $(1)): PRIVATE_OUT := $(strip $(1)))
 $(eval $(strip $(1)): PRIVATE_IN := $(strip $(3)))
-$(strip $(1)): $(ACONFIG)
+$(strip $(1)): $(ACONFIG) $(strip $(3))
 	mkdir -p $$(dir $$(PRIVATE_OUT))
 	$$(if $$(PRIVATE_IN), \
 		$$(ACONFIG) dump --format textproto --out $$(PRIVATE_OUT) \
diff --git a/core/product.mk b/core/product.mk
index b66f1e2..bf85c78 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -430,6 +430,9 @@
 # specified we default to COW version 2 in update_engine for backwards compatibility
 _product_single_value_vars += PRODUCT_VIRTUAL_AB_COW_VERSION
 
+# If set, determines whether the build system checks vendor seapp contexts violations.
+_product_single_value_vars += PRODUCT_CHECK_VENDOR_SEAPP_VIOLATIONS
+
 _product_list_vars += PRODUCT_AFDO_PROFILES
 
 .KATI_READONLY := _product_single_value_vars _product_list_vars
diff --git a/core/product_config.mk b/core/product_config.mk
index 3f9eb24..832d6ad 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -572,6 +572,32 @@
       $(PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS))
 endif
 
+# Get the board API level.
+board_api_level := $(PLATFORM_SDK_VERSION)
+ifdef BOARD_API_LEVEL
+  board_api_level := $(BOARD_API_LEVEL)
+else ifdef BOARD_SHIPPING_API_LEVEL
+  # Vendors with GRF must define BOARD_SHIPPING_API_LEVEL for the vendor API level.
+  board_api_level := $(BOARD_SHIPPING_API_LEVEL)
+endif
+
+# Calculate the VSR vendor API level.
+VSR_VENDOR_API_LEVEL := $(board_api_level)
+
+ifdef PRODUCT_SHIPPING_API_LEVEL
+  VSR_VENDOR_API_LEVEL := $(call math_min,$(PRODUCT_SHIPPING_API_LEVEL),$(board_api_level))
+endif
+.KATI_READONLY := VSR_VENDOR_API_LEVEL
+
+# Boolean variable determining if vendor seapp contexts is enforced
+CHECK_VENDOR_SEAPP_VIOLATIONS := false
+ifneq ($(call math_gt,$(VSR_VENDOR_API_LEVEL),34),)
+  CHECK_VENDOR_SEAPP_VIOLATIONS := true
+else ifneq ($(PRODUCT_CHECK_VENDOR_SEAPP_VIOLATIONS),)
+  CHECK_VENDOR_SEAPP_VIOLATIONS := $(PRODUCT_CHECK_VENDOR_SEAPP_VIOLATIONS)
+endif
+.KATI_READONLY := CHECK_VENDOR_SEAPP_VIOLATIONS
+
 define product-overrides-config
 $$(foreach rule,$$(PRODUCT_$(1)_OVERRIDES),\
     $$(if $$(filter 2,$$(words $$(subst :,$$(space),$$(rule)))),,\
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 26998ed..7d8092d 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -324,6 +324,8 @@
 
 $(call add_json_bool, KeepVndk, $(filter true,$(KEEP_VNDK)))
 
+$(call add_json_bool, CheckVendorSeappViolations, $(filter true,$(CHECK_VENDOR_SEAPP_VIOLATIONS)))
+
 $(call json_end)
 
 $(file >$(SOONG_VARIABLES).tmp,$(json_contents))
diff --git a/core/sysprop.mk b/core/sysprop.mk
index 451e88a..4536e5f 100644
--- a/core/sysprop.mk
+++ b/core/sysprop.mk
@@ -47,9 +47,21 @@
         echo "ro.product.$(1).model=$(PRODUCT_MODEL)" >> $(2);\
         echo "ro.product.$(1).name=$(TARGET_PRODUCT)" >> $(2);\
         # Attestation specific properties for AOSP/GSI build running on device.
-        echo "ro.product.model_for_attestation=$(PRODUCT_MODEL_FOR_ATTESTATION)" >> $(2);\
-        echo "ro.product.brand_for_attestation=$(PRODUCT_BRAND_FOR_ATTESTATION)" >> $(2);\
-        echo "ro.product.name_for_attestation=$(PRODUCT_NAME_FOR_ATTESTATION)" >> $(2);\
+        if [ -n "$(strip $(PRODUCT_MODEL_FOR_ATTESTATION))" ]; then \
+            echo "ro.product.model_for_attestation=$(PRODUCT_MODEL_FOR_ATTESTATION)" >> $(2);\
+        fi; \
+        if [ -n "$(strip $(PRODUCT_BRAND_FOR_ATTESTATION))" ]; then \
+            echo "ro.product.brand_for_attestation=$(PRODUCT_BRAND_FOR_ATTESTATION)" >> $(2);\
+        fi; \
+        if [ -n "$(strip $(PRODUCT_NAME_FOR_ATTESTATION))" ]; then \
+            echo "ro.product.name_for_attestation=$(PRODUCT_NAME_FOR_ATTESTATION)" >> $(2);\
+        fi; \
+        if [ -n "$(strip $(PRODUCT_DEVICE_FOR_ATTESTATION))" ]; then \
+            echo "ro.product.device_for_attestation=$(PRODUCT_DEVICE_FOR_ATTESTATION)" >> $(2);\
+        fi; \
+        if [ -n "$(strip $(PRODUCT_MANUFACTURER_FOR_ATTESTATION))" ]; then \
+            echo "ro.product.manufacturer_for_attestation=$(PRODUCT_MANUFACTURER_FOR_ATTESTATION)" >> $(2);\
+        fi; \
     )\
     $(if $(filter true,$(ZYGOTE_FORCE_64)),\
         $(if $(filter vendor,$(1)),\
diff --git a/core/tasks/cts.mk b/core/tasks/cts.mk
index c8b1183..593b7b6 100644
--- a/core/tasks/cts.mk
+++ b/core/tasks/cts.mk
@@ -37,16 +37,18 @@
   cts_platform_release_path := cts/tests/tests/os/assets/platform_releases.txt
   cts_platform_release_string := $(shell cat $(cts_platform_release_path))
 
-  ifeq (,$(findstring $(PLATFORM_VERSION),$(cts_platform_version_string)))
-    define error_msg
-      ============================================================
-      Could not find version "$(PLATFORM_VERSION)" in CTS platform version file:
-      $(cts_platform_version_path)
-      Most likely PLATFORM_VERSION in build/core/version_defaults.mk
-      has changed and a new version must be added to this CTS file.
-      ============================================================
-    endef
-    $(error $(error_msg))
+  ifeq ($(RELEASE_PLATFORM_VERSION_CODENAME_REL),)
+    ifeq (,$(findstring $(PLATFORM_VERSION),$(cts_platform_version_string)))
+      define error_msg
+        ============================================================
+        Could not find version "$(PLATFORM_VERSION)" in CTS platform version file:
+        $(cts_platform_version_path)
+        Most likely PLATFORM_VERSION in build/core/version_defaults.mk
+        has changed and a new version must be added to this CTS file.
+        ============================================================
+      endef
+      $(error $(error_msg))
+    endif
   endif
   ifeq (,$(findstring $(PLATFORM_VERSION_LAST_STABLE),$(cts_platform_release_string)))
     define error_msg
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 6dd85f0..03de6a8 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -70,7 +70,6 @@
     com.android.scheduling \
     com.android.sdkext \
     com.android.tethering \
-    com.android.threadnetwork \
     com.android.tzdata \
     com.android.uwb \
     com.android.virt \
@@ -386,6 +385,7 @@
 # Packages included only for eng or userdebug builds, previously debug tagged
 PRODUCT_PACKAGES_DEBUG := \
     adb_keys \
+    adevice_fingerprint \
     arping \
     dmuserd \
     idlcli \
@@ -432,3 +432,6 @@
     frameworks/base/config/dirty-image-objects:system/etc/dirty-image-objects)
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/runtime_libart.mk)
+
+# Use "image" APEXes always.
+$(call inherit-product,$(SRC_TARGET_DIR)/product/updatable_apex.mk)
diff --git a/target/product/default_art_config.mk b/target/product/default_art_config.mk
index f82d177..3ca4187 100644
--- a/target/product/default_art_config.mk
+++ b/target/product/default_art_config.mk
@@ -111,7 +111,6 @@
     com.android.os.statsd:service-statsd \
     com.android.scheduling:service-scheduling \
     com.android.tethering:service-connectivity \
-    com.android.threadnetwork:service-threadnetwork \
     com.android.uwb:service-uwb \
     com.android.wifi:service-wifi \
 
diff --git a/target/product/generic_system.mk b/target/product/generic_system.mk
index 1a639ef..f194d8b 100644
--- a/target/product/generic_system.mk
+++ b/target/product/generic_system.mk
@@ -102,6 +102,11 @@
     libaudiopolicyengineconfigurable \
     libpolicy-subsystem
 
+
+ifneq ($(KEEP_VNDK),true)
+PRODUCT_PACKAGES += llndk.libraries.txt
+endif
+
 # Include all zygote init scripts. "ro.zygote" will select one of them.
 PRODUCT_COPY_FILES += \
     system/core/rootdir/init.zygote32.rc:system/etc/init/hw/init.zygote32.rc \
diff --git a/target/product/gsi/Android.mk b/target/product/gsi/Android.mk
index 86d4622..adeb159 100644
--- a/target/product/gsi/Android.mk
+++ b/target/product/gsi/Android.mk
@@ -195,7 +195,10 @@
 include $(CLEAR_VARS)
 _vndk_versions :=
 ifeq ($(filter com.android.vndk.current.on_vendor, $(PRODUCT_PACKAGES)),)
-	_vndk_versions += $(PRODUCT_EXTRA_VNDK_VERSIONS)
+	_vndk_versions += $(if $(call math_is_number,$(PLATFORM_VNDK_VERSION)),\
+		$(foreach vndk_ver,$(PRODUCT_EXTRA_VNDK_VERSIONS),\
+			$(if $(call math_lt,$(vndk_ver),$(PLATFORM_VNDK_VERSION)),$(vndk_ver))),\
+		$(PRODUCT_EXTRA_VNDK_VERSIONS))
 endif
 ifneq ($(BOARD_VNDK_VERSION),current)
 	_vndk_versions += $(BOARD_VNDK_VERSION)
diff --git a/target/product/gsi_release.mk b/target/product/gsi_release.mk
index e39af92..bd85b9f 100644
--- a/target/product/gsi_release.mk
+++ b/target/product/gsi_release.mk
@@ -28,10 +28,15 @@
 
 BUILDING_GSI := true
 
-# Exclude all files under system/product and system/system_ext
+# Exclude all files under system/product and system/system_ext,
+# and the vndk apex's compat symlinks
 PRODUCT_ARTIFACT_PATH_REQUIREMENT_ALLOWED_LIST += \
     system/product/% \
-    system/system_ext/%
+    system/system_ext/% \
+    system/lib/vndk-29 \
+    system/lib/vndk-sp-29 \
+    system/lib64/vndk-29 \
+    system/lib64/vndk-sp-29
 
 # GSI should always support up-to-date platform features.
 # Keep this value at the latest API level to ensure latest build system
diff --git a/target/product/updatable_apex.mk b/target/product/updatable_apex.mk
index c19982b..8357fdf 100644
--- a/target/product/updatable_apex.mk
+++ b/target/product/updatable_apex.mk
@@ -14,17 +14,13 @@
 # limitations under the License.
 #
 
-# Inherit this when the target needs to support updating APEXes
+# com.android.apex.cts.shim.v1_prebuilt overrides CtsShimPrebuilt
+# and CtsShimPrivPrebuilt since they are packaged inside the APEX.
+PRODUCT_PACKAGES += com.android.apex.cts.shim.v1_prebuilt
+PRODUCT_SYSTEM_PROPERTIES := ro.apex.updatable=true
 
-ifneq ($(OVERRIDE_TARGET_FLATTEN_APEX),true)
-  # com.android.apex.cts.shim.v1_prebuilt overrides CtsShimPrebuilt
-  # and CtsShimPrivPrebuilt since they are packaged inside the APEX.
-  PRODUCT_PACKAGES += com.android.apex.cts.shim.v1_prebuilt
-  PRODUCT_SYSTEM_PROPERTIES := ro.apex.updatable=true
-  TARGET_FLATTEN_APEX := false
-  # Use compressed apexes in pre-installed partitions.
-  # Note: this doesn't mean that all pre-installed apexes will be compressed.
-  #  Whether an apex is compressed or not is controlled at apex Soong module
-  #  via compresible property.
-  PRODUCT_COMPRESSED_APEX := true
-endif
+# Use compressed apexes in pre-installed partitions.
+# Note: this doesn't mean that all pre-installed apexes will be compressed.
+#  Whether an apex is compressed or not is controlled at apex Soong module
+#  via compresible property.
+PRODUCT_COMPRESSED_APEX := true
diff --git a/tools/BUILD.bazel b/tools/BUILD.bazel
index 0de178b..2dbb585 100644
--- a/tools/BUILD.bazel
+++ b/tools/BUILD.bazel
@@ -1,6 +1,7 @@
 py_library(
     name = "event_log_tags",
     srcs = ["event_log_tags.py"],
+    imports = ["."],
 )
 
 py_binary(
diff --git a/tools/aconfig/TEST_MAPPING b/tools/aconfig/TEST_MAPPING
index 86124dd..74ac5ec 100644
--- a/tools/aconfig/TEST_MAPPING
+++ b/tools/aconfig/TEST_MAPPING
@@ -10,6 +10,12 @@
           "include-filter": "android.cts.flags.tests.FlagAnnotationTest"
         }
       ]
+    },
+    {
+      // Ensure changes on aconfig auto generated library is compatible with
+      // test testing filtering logic. Breakage on this test means all tests
+      // that using the flag macros to do filtering will get affected.
+      "name": "FlagMacrosTests"
     }
   ]
 }
diff --git a/tools/aconfig/fake_device_config/Android.bp b/tools/aconfig/fake_device_config/Android.bp
new file mode 100644
index 0000000..810ec04
--- /dev/null
+++ b/tools/aconfig/fake_device_config/Android.bp
@@ -0,0 +1,20 @@
+// 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.
+
+java_library {
+	name: "fake_device_config",
+	srcs: ["src/**/*.java"],
+	sdk_version: "core_platform",
+}
+
diff --git a/tools/aconfig/fake_device_config/src/android/provider/DeviceConfig.java b/tools/aconfig/fake_device_config/src/android/provider/DeviceConfig.java
new file mode 100644
index 0000000..50b6289
--- /dev/null
+++ b/tools/aconfig/fake_device_config/src/android/provider/DeviceConfig.java
@@ -0,0 +1,29 @@
+/*
+ * 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.
+ */
+
+package android.provider;
+
+/*
+ * This class allows generated aconfig code to compile independently of the framework.
+ */
+public class DeviceConfig {
+	private DeviceConfig() {
+	}
+
+	public static boolean getBoolean(String ns, String name, boolean def) {
+		return false;
+	}
+}
diff --git a/tools/aconfig/protos/aconfig.proto b/tools/aconfig/protos/aconfig.proto
index 4cad69a..d5e2868 100644
--- a/tools/aconfig/protos/aconfig.proto
+++ b/tools/aconfig/protos/aconfig.proto
@@ -39,6 +39,7 @@
   optional string namespace = 2;
   optional string description = 3;
   repeated string bug = 4;
+  optional bool is_fixed_read_only = 5;
 };
 
 message flag_declarations {
@@ -75,6 +76,7 @@
   optional flag_state state = 6;
   optional flag_permission permission = 7;
   repeated tracepoint trace = 8;
+  optional bool is_fixed_read_only = 9;
 }
 
 message parsed_flags {
diff --git a/tools/aconfig/src/codegen_cpp.rs b/tools/aconfig/src/codegen_cpp.rs
index 30e564a..8c2d7ba 100644
--- a/tools/aconfig/src/codegen_cpp.rs
+++ b/tools/aconfig/src/codegen_cpp.rs
@@ -131,6 +131,8 @@
 
     virtual bool disabled_rw() = 0;
 
+    virtual bool enabled_fixed_ro() = 0;
+
     virtual bool enabled_ro() = 0;
 
     virtual bool enabled_rw() = 0;
@@ -146,6 +148,10 @@
     return provider_->disabled_rw();
 }
 
+inline bool enabled_fixed_ro() {
+    return true;
+}
+
 inline bool enabled_ro() {
     return true;
 }
@@ -163,6 +169,8 @@
 
 bool com_android_aconfig_test_disabled_rw();
 
+bool com_android_aconfig_test_enabled_fixed_ro();
+
 bool com_android_aconfig_test_enabled_ro();
 
 bool com_android_aconfig_test_enabled_rw();
@@ -194,6 +202,10 @@
 
     virtual void disabled_rw(bool val) = 0;
 
+    virtual bool enabled_fixed_ro() = 0;
+
+    virtual void enabled_fixed_ro(bool val) = 0;
+
     virtual bool enabled_ro() = 0;
 
     virtual void enabled_ro(bool val) = 0;
@@ -223,6 +235,14 @@
     provider_->disabled_rw(val);
 }
 
+inline bool enabled_fixed_ro() {
+    return provider_->enabled_fixed_ro();
+}
+
+inline void enabled_fixed_ro(bool val) {
+    provider_->enabled_fixed_ro(val);
+}
+
 inline bool enabled_ro() {
     return provider_->enabled_ro();
 }
@@ -256,6 +276,10 @@
 
 void set_com_android_aconfig_test_disabled_rw(bool val);
 
+bool com_android_aconfig_test_enabled_fixed_ro();
+
+void set_com_android_aconfig_test_enabled_fixed_ro(bool val);
+
 bool com_android_aconfig_test_enabled_ro();
 
 void set_com_android_aconfig_test_enabled_ro(bool val);
@@ -294,6 +318,10 @@
                     "false") == "true";
             }
 
+            virtual bool enabled_fixed_ro() override {
+                return true;
+            }
+
             virtual bool enabled_ro() override {
                 return true;
             }
@@ -319,6 +347,10 @@
     return com::android::aconfig::test::disabled_rw();
 }
 
+bool com_android_aconfig_test_enabled_fixed_ro() {
+    return true;
+}
+
 bool com_android_aconfig_test_enabled_ro() {
     return true;
 }
@@ -373,6 +405,19 @@
                 overrides_["disabled_rw"] = val;
             }
 
+            virtual bool enabled_fixed_ro() override {
+                auto it = overrides_.find("enabled_fixed_ro");
+                  if (it != overrides_.end()) {
+                      return it->second;
+                } else {
+                  return true;
+                }
+            }
+
+            virtual void enabled_fixed_ro(bool val) override {
+                overrides_["enabled_fixed_ro"] = val;
+            }
+
             virtual bool enabled_ro() override {
                 auto it = overrides_.find("enabled_ro");
                   if (it != overrides_.end()) {
@@ -402,7 +447,6 @@
                 overrides_["enabled_rw"] = val;
             }
 
-
             virtual void reset_flags() override {
                 overrides_.clear();
             }
@@ -430,6 +474,16 @@
     com::android::aconfig::test::disabled_rw(val);
 }
 
+
+bool com_android_aconfig_test_enabled_fixed_ro() {
+    return com::android::aconfig::test::enabled_fixed_ro();
+}
+
+void set_com_android_aconfig_test_enabled_fixed_ro(bool val) {
+    com::android::aconfig::test::enabled_fixed_ro(val);
+}
+
+
 bool com_android_aconfig_test_enabled_ro() {
     return com::android::aconfig::test::enabled_ro();
 }
diff --git a/tools/aconfig/src/codegen_java.rs b/tools/aconfig/src/codegen_java.rs
index 2c9dcf5..7cdf486 100644
--- a/tools/aconfig/src/codegen_java.rs
+++ b/tools/aconfig/src/codegen_java.rs
@@ -121,8 +121,10 @@
     public interface FeatureFlags {
         boolean disabledRo();
         boolean disabledRw();
+        boolean enabledFixedRo();
         boolean enabledRo();
         boolean enabledRw();
+    }
     "#;
 
     const EXPECTED_FLAG_COMMON_CONTENT: &str = r#"
@@ -130,6 +132,7 @@
     public final class Flags {
         public static final String FLAG_DISABLED_RO = "com.android.aconfig.test.disabled_ro";
         public static final String FLAG_DISABLED_RW = "com.android.aconfig.test.disabled_rw";
+        public static final String FLAG_ENABLED_FIXED_RO = "com.android.aconfig.test.enabled_fixed_ro";
         public static final String FLAG_ENABLED_RO = "com.android.aconfig.test.enabled_ro";
         public static final String FLAG_ENABLED_RW = "com.android.aconfig.test.enabled_rw";
 
@@ -139,6 +142,9 @@
         public static boolean disabledRw() {
             return FEATURE_FLAGS.disabledRw();
         }
+        public static boolean enabledFixedRo() {
+            return FEATURE_FLAGS.enabledFixedRo();
+        }
         public static boolean enabledRo() {
             return FEATURE_FLAGS.enabledRo();
         }
@@ -147,27 +153,62 @@
         }
     "#;
 
-    const EXPECTED_METHOD_NOT_IMPL_COMMON_CONTENT: &str = r#"
+    const EXPECTED_FAKEFEATUREFLAGSIMPL_CONTENT: &str = r#"
+    package com.android.aconfig.test;
+    import java.util.HashMap;
+    import java.util.Map;
+    public class FakeFeatureFlagsImpl implements FeatureFlags {
+        public FakeFeatureFlagsImpl() {
+            resetAll();
+        }
         @Override
         public boolean disabledRo() {
-            throw new UnsupportedOperationException(
-                "Method is not implemented.");
+            return getFlag(Flags.FLAG_DISABLED_RO);
         }
         @Override
         public boolean disabledRw() {
-            throw new UnsupportedOperationException(
-                "Method is not implemented.");
+            return getFlag(Flags.FLAG_DISABLED_RW);
+        }
+        @Override
+        public boolean enabledFixedRo() {
+            return getFlag(Flags.FLAG_ENABLED_FIXED_RO);
         }
         @Override
         public boolean enabledRo() {
-            throw new UnsupportedOperationException(
-                "Method is not implemented.");
+            return getFlag(Flags.FLAG_ENABLED_RO);
         }
         @Override
         public boolean enabledRw() {
-            throw new UnsupportedOperationException(
-                "Method is not implemented.");
+            return getFlag(Flags.FLAG_ENABLED_RW);
         }
+        public void setFlag(String flagName, boolean value) {
+            if (!this.mFlagMap.containsKey(flagName)) {
+                throw new IllegalArgumentException("no such flag " + flagName);
+            }
+            this.mFlagMap.put(flagName, value);
+        }
+        public void resetAll() {
+            for (Map.Entry entry : mFlagMap.entrySet()) {
+                entry.setValue(null);
+            }
+        }
+        private boolean getFlag(String flagName) {
+            Boolean value = this.mFlagMap.get(flagName);
+            if (value == null) {
+                throw new IllegalArgumentException(flagName + " is not set");
+            }
+            return value;
+        }
+        private Map<String, Boolean> mFlagMap = new HashMap<>(
+            Map.of(
+                Flags.FLAG_DISABLED_RO, false,
+                Flags.FLAG_DISABLED_RW, false,
+                Flags.FLAG_ENABLED_FIXED_RO, false,
+                Flags.FLAG_ENABLED_RO, false,
+                Flags.FLAG_ENABLED_RW, false
+            )
+        );
+    }
     "#;
 
     #[test]
@@ -179,21 +220,11 @@
             CodegenMode::Production,
         )
         .unwrap();
-        let expect_featureflags_content = EXPECTED_FEATUREFLAGS_COMMON_CONTENT.to_string()
-            + r#"
-        }"#;
         let expect_flags_content = EXPECTED_FLAG_COMMON_CONTENT.to_string()
             + r#"
             private static FeatureFlags FEATURE_FLAGS = new FeatureFlagsImpl();
         }"#;
-        let expect_fakefeatureflagsimpl_content = r#"
-        package com.android.aconfig.test;
-        public class FakeFeatureFlagsImpl implements FeatureFlags {"#
-            .to_owned()
-            + EXPECTED_METHOD_NOT_IMPL_COMMON_CONTENT
-            + r#"
-        }
-        "#;
+
         let expect_featureflagsimpl_content = r#"
         package com.android.aconfig.test;
         import android.provider.DeviceConfig;
@@ -211,6 +242,10 @@
                 );
             }
             @Override
+            public boolean enabledFixedRo() {
+                return true;
+            }
+            @Override
             public boolean enabledRo() {
                 return true;
             }
@@ -227,10 +262,10 @@
         let mut file_set = HashMap::from([
             ("com/android/aconfig/test/Flags.java", expect_flags_content.as_str()),
             ("com/android/aconfig/test/FeatureFlagsImpl.java", expect_featureflagsimpl_content),
-            ("com/android/aconfig/test/FeatureFlags.java", expect_featureflags_content.as_str()),
+            ("com/android/aconfig/test/FeatureFlags.java", EXPECTED_FEATUREFLAGS_COMMON_CONTENT),
             (
                 "com/android/aconfig/test/FakeFeatureFlagsImpl.java",
-                expect_fakefeatureflagsimpl_content.as_str(),
+                EXPECTED_FAKEFEATUREFLAGSIMPL_CONTENT,
             ),
         ]);
 
@@ -261,11 +296,7 @@
             CodegenMode::Test,
         )
         .unwrap();
-        let expect_featureflags_content = EXPECTED_FEATUREFLAGS_COMMON_CONTENT.to_string()
-            + r#"
-            public void setFlag(String flagName, boolean value);
-            public void resetAll();
-        }"#;
+
         let expect_flags_content = EXPECTED_FLAG_COMMON_CONTENT.to_string()
             + r#"
             public static void setFeatureFlags(FeatureFlags featureFlags) {
@@ -279,89 +310,42 @@
         "#;
         let expect_featureflagsimpl_content = r#"
         package com.android.aconfig.test;
-        public final class FeatureFlagsImpl implements FeatureFlags {"#
-            .to_owned()
-            + EXPECTED_METHOD_NOT_IMPL_COMMON_CONTENT
-            + r#"
-            @Override
-            public void setFlag(String flagName, boolean value) {
-                throw new UnsupportedOperationException(
-                    "Method is not implemented.");
-            }
-            @Override
-            public void resetAll() {
-                throw new UnsupportedOperationException(
-                    "Method is not implemented.");
-            }
-        }
-        "#;
-        let expect_fakefeatureflagsimpl_content = r#"
-        package com.android.aconfig.test;
-        import static java.util.stream.Collectors.toMap;
-        import java.util.HashMap;
-        import java.util.Map;
-        import java.util.stream.Stream;
-        public class FakeFeatureFlagsImpl implements FeatureFlags {
+        public final class FeatureFlagsImpl implements FeatureFlags {
             @Override
             public boolean disabledRo() {
-                return getFlag(Flags.FLAG_DISABLED_RO);
+                throw new UnsupportedOperationException(
+                    "Method is not implemented.");
             }
             @Override
             public boolean disabledRw() {
-                return getFlag(Flags.FLAG_DISABLED_RW);
+                throw new UnsupportedOperationException(
+                    "Method is not implemented.");
+            }
+            @Override
+            public boolean enabledFixedRo() {
+                throw new UnsupportedOperationException(
+                    "Method is not implemented.");
             }
             @Override
             public boolean enabledRo() {
-                return getFlag(Flags.FLAG_ENABLED_RO);
+                throw new UnsupportedOperationException(
+                    "Method is not implemented.");
             }
             @Override
             public boolean enabledRw() {
-                return getFlag(Flags.FLAG_ENABLED_RW);
+                throw new UnsupportedOperationException(
+                    "Method is not implemented.");
             }
-            @Override
-            public void setFlag(String flagName, boolean value) {
-                if (!this.mFlagMap.containsKey(flagName)) {
-                    throw new IllegalArgumentException("no such flag" + flagName);
-                }
-                this.mFlagMap.put(flagName, value);
-            }
-            @Override
-            public void resetAll() {
-                for (Map.Entry entry : mFlagMap.entrySet()) {
-                    entry.setValue(null);
-                }
-            }
-            private boolean getFlag(String flagName) {
-                Boolean value = this.mFlagMap.get(flagName);
-                if (value == null) {
-                    throw new IllegalArgumentException(flagName + " is not set");
-                }
-                return value;
-            }
-            private HashMap<String, Boolean> mFlagMap = Stream.of(
-                    Flags.FLAG_DISABLED_RO,
-                    Flags.FLAG_DISABLED_RW,
-                    Flags.FLAG_ENABLED_RO,
-                    Flags.FLAG_ENABLED_RW
-                )
-                .collect(
-                    HashMap::new,
-                    (map, elem) -> map.put(elem, null),
-                    HashMap::putAll
-                );
         }
         "#;
 
         let mut file_set = HashMap::from([
             ("com/android/aconfig/test/Flags.java", expect_flags_content.as_str()),
-            ("com/android/aconfig/test/FeatureFlags.java", expect_featureflags_content.as_str()),
-            (
-                "com/android/aconfig/test/FeatureFlagsImpl.java",
-                expect_featureflagsimpl_content.as_str(),
-            ),
+            ("com/android/aconfig/test/FeatureFlags.java", EXPECTED_FEATUREFLAGS_COMMON_CONTENT),
+            ("com/android/aconfig/test/FeatureFlagsImpl.java", expect_featureflagsimpl_content),
             (
                 "com/android/aconfig/test/FakeFeatureFlagsImpl.java",
-                expect_fakefeatureflagsimpl_content,
+                EXPECTED_FAKEFEATUREFLAGSIMPL_CONTENT,
             ),
         ]);
 
diff --git a/tools/aconfig/src/codegen_rust.rs b/tools/aconfig/src/codegen_rust.rs
index 0234eb2..4e4c7dd 100644
--- a/tools/aconfig/src/codegen_rust.rs
+++ b/tools/aconfig/src/codegen_rust.rs
@@ -108,6 +108,11 @@
             "false") == "true"
     }
 
+    /// query flag enabled_fixed_ro
+    pub fn enabled_fixed_ro(&self) -> bool {
+        true
+    }
+
     /// query flag enabled_ro
     pub fn enabled_ro(&self) -> bool {
         true
@@ -137,6 +142,12 @@
     PROVIDER.disabled_rw()
 }
 
+/// query flag enabled_fixed_ro
+#[inline(always)]
+pub fn enabled_fixed_ro() -> bool {
+    true
+}
+
 /// query flag enabled_ro
 #[inline(always)]
 pub fn enabled_ro() -> bool {
@@ -189,6 +200,18 @@
         self.overrides.insert("disabled_rw", val);
     }
 
+    /// query flag enabled_fixed_ro
+    pub fn enabled_fixed_ro(&self) -> bool {
+        self.overrides.get("enabled_fixed_ro").copied().unwrap_or(
+            true
+        )
+    }
+
+    /// set flag enabled_fixed_ro
+    pub fn set_enabled_fixed_ro(&mut self, val: bool) {
+        self.overrides.insert("enabled_fixed_ro", val);
+    }
+
     /// query flag enabled_ro
     pub fn enabled_ro(&self) -> bool {
         self.overrides.get("enabled_ro").copied().unwrap_or(
@@ -251,6 +274,18 @@
     PROVIDER.lock().unwrap().set_disabled_rw(val);
 }
 
+/// query flag enabled_fixed_ro
+#[inline(always)]
+pub fn enabled_fixed_ro() -> bool {
+    PROVIDER.lock().unwrap().enabled_fixed_ro()
+}
+
+/// set flag enabled_fixed_ro
+#[inline(always)]
+pub fn set_enabled_fixed_ro(val: bool) {
+    PROVIDER.lock().unwrap().set_enabled_fixed_ro(val);
+}
+
 /// query flag enabled_ro
 #[inline(always)]
 pub fn enabled_ro() -> bool {
diff --git a/tools/aconfig/src/commands.rs b/tools/aconfig/src/commands.rs
index ab5b0f2..e4baa82 100644
--- a/tools/aconfig/src/commands.rs
+++ b/tools/aconfig/src/commands.rs
@@ -91,11 +91,17 @@
             parsed_flag.set_description(flag_declaration.take_description());
             parsed_flag.bug.append(&mut flag_declaration.bug);
             parsed_flag.set_state(DEFAULT_FLAG_STATE);
-            parsed_flag.set_permission(default_permission);
+            let flag_permission = if flag_declaration.is_fixed_read_only() {
+                ProtoFlagPermission::READ_ONLY
+            } else {
+                default_permission
+            };
+            parsed_flag.set_permission(flag_permission);
+            parsed_flag.set_is_fixed_read_only(flag_declaration.is_fixed_read_only());
             let mut tracepoint = ProtoTracepoint::new();
             tracepoint.set_source(input.source.clone());
             tracepoint.set_state(DEFAULT_FLAG_STATE);
-            tracepoint.set_permission(default_permission);
+            tracepoint.set_permission(flag_permission);
             parsed_flag.trace.push(tracepoint);
 
             // verify ParsedFlag looks reasonable
@@ -135,6 +141,13 @@
                 continue;
             };
 
+            ensure!(
+                !parsed_flag.is_fixed_read_only()
+                    || flag_value.permission() == ProtoFlagPermission::READ_ONLY,
+                "failed to set permission of flag {}, since this flag is fixed read only flag",
+                flag_value.name()
+            );
+
             parsed_flag.set_state(flag_value.state());
             parsed_flag.set_permission(flag_value.permission());
             let mut tracepoint = ProtoTracepoint::new();
@@ -310,6 +323,7 @@
         assert_eq!(ProtoFlagState::ENABLED, enabled_ro.state());
         assert_eq!(ProtoFlagPermission::READ_ONLY, enabled_ro.permission());
         assert_eq!(3, enabled_ro.trace.len());
+        assert!(!enabled_ro.is_fixed_read_only());
         assert_eq!("tests/test.aconfig", enabled_ro.trace[0].source());
         assert_eq!(ProtoFlagState::DISABLED, enabled_ro.trace[0].state());
         assert_eq!(ProtoFlagPermission::READ_WRITE, enabled_ro.trace[0].permission());
@@ -320,8 +334,11 @@
         assert_eq!(ProtoFlagState::ENABLED, enabled_ro.trace[2].state());
         assert_eq!(ProtoFlagPermission::READ_ONLY, enabled_ro.trace[2].permission());
 
-        assert_eq!(4, parsed_flags.parsed_flag.len());
+        assert_eq!(5, parsed_flags.parsed_flag.len());
         for pf in parsed_flags.parsed_flag.iter() {
+            if pf.name() == "enabled_fixed_ro" {
+                continue;
+            }
             let first = pf.trace.first().unwrap();
             assert_eq!(DEFAULT_FLAG_STATE, first.state());
             assert_eq!(DEFAULT_FLAG_PERMISSION, first.permission());
@@ -330,6 +347,15 @@
             assert_eq!(pf.state(), last.state());
             assert_eq!(pf.permission(), last.permission());
         }
+
+        let enabled_fixed_ro =
+            parsed_flags.parsed_flag.iter().find(|pf| pf.name() == "enabled_fixed_ro").unwrap();
+        assert!(enabled_fixed_ro.is_fixed_read_only());
+        assert_eq!(ProtoFlagState::ENABLED, enabled_fixed_ro.state());
+        assert_eq!(ProtoFlagPermission::READ_ONLY, enabled_fixed_ro.permission());
+        assert_eq!(2, enabled_fixed_ro.trace.len());
+        assert_eq!(ProtoFlagPermission::READ_ONLY, enabled_fixed_ro.trace[0].permission());
+        assert_eq!(ProtoFlagPermission::READ_ONLY, enabled_fixed_ro.trace[1].permission());
     }
 
     #[test]
@@ -363,6 +389,46 @@
     }
 
     #[test]
+    fn test_parse_flags_override_fixed_read_only() {
+        let first_flag = r#"
+        package: "com.first"
+        flag {
+            name: "first"
+            namespace: "first_ns"
+            description: "This is the description of the first flag."
+            bug: "123"
+            is_fixed_read_only: true
+        }
+        "#;
+        let declaration =
+            vec![Input { source: "memory".to_string(), reader: Box::new(first_flag.as_bytes()) }];
+
+        let first_flag_value = r#"
+        flag_value {
+            package: "com.first"
+            name: "first"
+            state: DISABLED
+            permission: READ_WRITE
+        }
+        "#;
+        let value = vec![Input {
+            source: "memory".to_string(),
+            reader: Box::new(first_flag_value.as_bytes()),
+        }];
+        let error = crate::commands::parse_flags(
+            "com.first",
+            declaration,
+            value,
+            ProtoFlagPermission::READ_WRITE,
+        )
+        .unwrap_err();
+        assert_eq!(
+            format!("{:?}", error),
+            "failed to set permission of flag first, since this flag is fixed read only flag"
+        );
+    }
+
+    #[test]
     fn test_create_device_config_defaults() {
         let input = parse_test_flags_as_input();
         let bytes = create_device_config_defaults(input).unwrap();
diff --git a/tools/aconfig/src/protos.rs b/tools/aconfig/src/protos.rs
index c3911e5..b93abcc 100644
--- a/tools/aconfig/src/protos.rs
+++ b/tools/aconfig/src/protos.rs
@@ -303,6 +303,7 @@
     namespace: "second_ns"
     description: "This is the description of the second flag."
     bug: "abc"
+    is_fixed_read_only: true
 }
 "#,
         )
@@ -313,11 +314,13 @@
         assert_eq!(first.namespace(), "first_ns");
         assert_eq!(first.description(), "This is the description of the first flag.");
         assert_eq!(first.bug, vec!["123"]);
+        assert!(!first.is_fixed_read_only());
         let second = flag_declarations.flag.iter().find(|pf| pf.name() == "second").unwrap();
         assert_eq!(second.name(), "second");
         assert_eq!(second.namespace(), "second_ns");
         assert_eq!(second.description(), "This is the description of the second flag.");
         assert_eq!(second.bug, vec!["abc"]);
+        assert!(second.is_fixed_read_only());
 
         // bad input: missing package in flag declarations
         let error = flag_declarations::try_from_text_proto(
@@ -555,6 +558,7 @@
         state: ENABLED
         permission: READ_WRITE
     }
+    is_fixed_read_only: true
 }
 "#;
         let parsed_flags = try_from_binary_proto_from_text_proto(text_proto).unwrap();
@@ -574,6 +578,7 @@
         assert_eq!(second.trace[1].source(), "flags.values");
         assert_eq!(second.trace[1].state(), ProtoFlagState::ENABLED);
         assert_eq!(second.trace[1].permission(), ProtoFlagPermission::READ_WRITE);
+        assert!(second.is_fixed_read_only());
 
         // valid input: empty
         let parsed_flags = try_from_binary_proto_from_text_proto("").unwrap();
diff --git a/tools/aconfig/src/test.rs b/tools/aconfig/src/test.rs
index 6c27885..9034704 100644
--- a/tools/aconfig/src/test.rs
+++ b/tools/aconfig/src/test.rs
@@ -41,6 +41,7 @@
     state: DISABLED
     permission: READ_ONLY
   }
+  is_fixed_read_only: false
 }
 parsed_flag {
   package: "com.android.aconfig.test"
@@ -55,6 +56,27 @@
     state: DISABLED
     permission: READ_WRITE
   }
+  is_fixed_read_only: false
+}
+parsed_flag {
+  package: "com.android.aconfig.test"
+  name: "enabled_fixed_ro"
+  namespace: "aconfig_test"
+  description: "This flag is fixed READ_ONLY + ENABLED"
+  bug: ""
+  state: ENABLED
+  permission: READ_ONLY
+  trace {
+    source: "tests/test.aconfig"
+    state: DISABLED
+    permission: READ_ONLY
+  }
+  trace {
+    source: "tests/first.values"
+    state: ENABLED
+    permission: READ_ONLY
+  }
+  is_fixed_read_only: true
 }
 parsed_flag {
   package: "com.android.aconfig.test"
@@ -79,6 +101,7 @@
     state: ENABLED
     permission: READ_ONLY
   }
+  is_fixed_read_only: false
 }
 parsed_flag {
   package: "com.android.aconfig.test"
@@ -98,6 +121,7 @@
     state: ENABLED
     permission: READ_WRITE
   }
+  is_fixed_read_only: false
 }
 "#;
 
diff --git a/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template b/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template
index dba82ef..82bea81 100644
--- a/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template
+++ b/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template
@@ -1,27 +1,26 @@
 package {package_name};
-{{ if is_test_mode }}
-import static java.util.stream.Collectors.toMap;
 
 import java.util.HashMap;
 import java.util.Map;
-import java.util.stream.Stream;
 
 public class FakeFeatureFlagsImpl implements FeatureFlags \{
+    public FakeFeatureFlagsImpl() \{
+        resetAll();
+    }
+
 {{ for item in class_elements}}
     @Override
     public boolean {item.method_name}() \{
         return getFlag(Flags.FLAG_{item.flag_name_constant_suffix});
     }
 {{ endfor}}
-    @Override
     public void setFlag(String flagName, boolean value) \{
         if (!this.mFlagMap.containsKey(flagName)) \{
-            throw new IllegalArgumentException("no such flag" + flagName);
+            throw new IllegalArgumentException("no such flag " + flagName);
         }
         this.mFlagMap.put(flagName, value);
     }
 
-    @Override
     public void resetAll() \{
         for (Map.Entry entry : mFlagMap.entrySet()) \{
             entry.setValue(null);
@@ -36,26 +35,11 @@
         return value;
     }
 
-    private HashMap<String, Boolean> mFlagMap = Stream.of(
+    private Map<String, Boolean> mFlagMap = new HashMap<>(
+        Map.of(
             {{-for item in class_elements}}
-            Flags.FLAG_{item.flag_name_constant_suffix}{{ if not @last }},{{ endif }}
+            Flags.FLAG_{item.flag_name_constant_suffix}, false{{ if not @last }},{{ endif }}
             {{ -endfor }}
         )
-        .collect(
-            HashMap::new,
-            (map, elem) -> map.put(elem, null),
-            HashMap::putAll
-        );
+    );
 }
-{{ else }}
-{#- Generate only stub if in prod mode #}
-public class FakeFeatureFlagsImpl implements FeatureFlags \{
-{{ for item in class_elements}}
-    @Override
-    public boolean {item.method_name}() \{
-        throw new UnsupportedOperationException(
-            "Method is not implemented.");
-    }
-{{ endfor}}
-}
-{{ endif }}
diff --git a/tools/aconfig/templates/FeatureFlags.java.template b/tools/aconfig/templates/FeatureFlags.java.template
index c99ccbb..e0f201f 100644
--- a/tools/aconfig/templates/FeatureFlags.java.template
+++ b/tools/aconfig/templates/FeatureFlags.java.template
@@ -4,10 +4,4 @@
 {{ for item in class_elements}}
     boolean {item.method_name}();
 {{ endfor }}
-
-{{ -if is_test_mode }}
-    public void setFlag(String flagName, boolean value);
-
-    public void resetAll();
-{{ -endif }}
 }
diff --git a/tools/aconfig/templates/FeatureFlagsImpl.java.template b/tools/aconfig/templates/FeatureFlagsImpl.java.template
index 7e1eb15..96de06c 100644
--- a/tools/aconfig/templates/FeatureFlagsImpl.java.template
+++ b/tools/aconfig/templates/FeatureFlagsImpl.java.template
@@ -17,7 +17,7 @@
         return {item.default_value};
     {{ endif- }}
     }
-{{ endfor- }}
+{{ endfor }}
 }
 {{ else }}
 {#- Generate only stub if in test mode #}
@@ -28,17 +28,6 @@
         throw new UnsupportedOperationException(
             "Method is not implemented.");
     }
-{{ endfor- }}
-    @Override
-    public void setFlag(String flagName, boolean value) \{
-        throw new UnsupportedOperationException(
-            "Method is not implemented.");
-    }
-
-    @Override
-    public void resetAll() \{
-        throw new UnsupportedOperationException(
-            "Method is not implemented.");
-    }
+{{ endfor }}
 }
 {{ endif }}
diff --git a/tools/aconfig/tests/AconfigHostTest.java b/tools/aconfig/tests/AconfigHostTest.java
index 29a01e3..ea71b7e 100644
--- a/tools/aconfig/tests/AconfigHostTest.java
+++ b/tools/aconfig/tests/AconfigHostTest.java
@@ -17,13 +17,13 @@
     @Test
     public void testThrowsExceptionIfFlagNotSet() {
         assertThrows(NullPointerException.class, () -> Flags.disabledRo());
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
+        FakeFeatureFlagsImpl featureFlags = new FakeFeatureFlagsImpl();
         assertThrows(IllegalArgumentException.class, () -> featureFlags.disabledRo());
     }
 
     @Test
     public void testSetFlagInFakeFeatureFlagsImpl() {
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
+        FakeFeatureFlagsImpl featureFlags = new FakeFeatureFlagsImpl();
         featureFlags.setFlag(Flags.FLAG_ENABLED_RW, true);
         assertTrue(featureFlags.enabledRw());
         featureFlags.setFlag(Flags.FLAG_ENABLED_RW, false);
@@ -39,14 +39,14 @@
 
     @Test
     public void testSetFlagWithRandomName() {
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
+        FakeFeatureFlagsImpl featureFlags = new FakeFeatureFlagsImpl();
         assertThrows(IllegalArgumentException.class,
             () -> featureFlags.setFlag("Randome_name", true));
     }
 
     @Test
     public void testResetFlagsInFakeFeatureFlagsImpl() {
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
+        FakeFeatureFlagsImpl featureFlags = new FakeFeatureFlagsImpl();
         featureFlags.setFlag(Flags.FLAG_ENABLED_RO, true);
         assertTrue(featureFlags.enabledRo());
         featureFlags.resetAll();
@@ -59,7 +59,7 @@
 
     @Test
     public void testFlagsSetFeatureFlags() {
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
+        FakeFeatureFlagsImpl featureFlags = new FakeFeatureFlagsImpl();
         featureFlags.setFlag(Flags.FLAG_ENABLED_RW, true);
         assertThrows(NullPointerException.class, () -> Flags.enabledRw());
         Flags.setFeatureFlags(featureFlags);
@@ -69,7 +69,7 @@
 
     @Test
     public void testFlagsUnsetFeatureFlags() {
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
+        FakeFeatureFlagsImpl featureFlags = new FakeFeatureFlagsImpl();
         featureFlags.setFlag(Flags.FLAG_ENABLED_RW, true);
         assertThrows(NullPointerException.class, () -> Flags.enabledRw());
         Flags.setFeatureFlags(featureFlags);
diff --git a/tools/aconfig/tests/AconfigTest.java b/tools/aconfig/tests/AconfigTest.java
index 317289d..958b02e 100644
--- a/tools/aconfig/tests/AconfigTest.java
+++ b/tools/aconfig/tests/AconfigTest.java
@@ -1,9 +1,11 @@
 import static com.android.aconfig.test.Flags.FLAG_DISABLED_RO;
 import static com.android.aconfig.test.Flags.FLAG_DISABLED_RW;
+import static com.android.aconfig.test.Flags.FLAG_ENABLED_FIXED_RO;
 import static com.android.aconfig.test.Flags.FLAG_ENABLED_RO;
 import static com.android.aconfig.test.Flags.FLAG_ENABLED_RW;
 import static com.android.aconfig.test.Flags.disabledRo;
 import static com.android.aconfig.test.Flags.disabledRw;
+import static com.android.aconfig.test.Flags.enabledFixedRo;
 import static com.android.aconfig.test.Flags.enabledRo;
 import static com.android.aconfig.test.Flags.enabledRw;
 import static org.junit.Assert.assertEquals;
@@ -35,6 +37,14 @@
     }
 
     @Test
+    public void testEnabledFixedReadOnlyFlag() {
+        assertEquals("com.android.aconfig.test.enabled_fixed_ro", FLAG_ENABLED_FIXED_RO);
+        // TODO: change to assertTrue(enabledFixedRo()) when the build supports reading tests/*.values
+        // (currently all flags are assigned the default READ_ONLY + DISABLED)
+        assertFalse(enabledFixedRo());
+    }
+
+    @Test
     public void testDisabledReadWriteFlag() {
         assertEquals("com.android.aconfig.test.enabled_ro", FLAG_ENABLED_RO);
         assertFalse(disabledRw());
@@ -49,8 +59,9 @@
     }
 
     @Test
-    public void testFakeFeatureFlagsImplNotImpl() {
-        FeatureFlags featureFlags = new FakeFeatureFlagsImpl();
-        assertThrows(UnsupportedOperationException.class, () -> featureFlags.enabledRw());
+    public void testFakeFeatureFlagsImplImpled() {
+        FakeFeatureFlagsImpl fakeFeatureFlags = new FakeFeatureFlagsImpl();
+        fakeFeatureFlags.setFlag(FLAG_ENABLED_RW, false);
+        assertFalse(fakeFeatureFlags.enabledRw());
     }
 }
diff --git a/tools/aconfig/tests/first.values b/tools/aconfig/tests/first.values
index e524404..a450f78 100644
--- a/tools/aconfig/tests/first.values
+++ b/tools/aconfig/tests/first.values
@@ -16,3 +16,9 @@
     state: ENABLED
     permission: READ_WRITE
 }
+flag_value {
+    package: "com.android.aconfig.test"
+    name: "enabled_fixed_ro"
+    state: ENABLED
+    permission: READ_ONLY
+}
diff --git a/tools/aconfig/tests/test.aconfig b/tools/aconfig/tests/test.aconfig
index 46cf1e9..aaa6df5 100644
--- a/tools/aconfig/tests/test.aconfig
+++ b/tools/aconfig/tests/test.aconfig
@@ -40,3 +40,14 @@
     description: "This flag is DISABLED + READ_WRITE"
     bug: "456"
 }
+
+# This flag's final value calculated from:
+# - test.aconfig: DISABLED + READ_ONLY
+# - first.values: ENABLED + READ_ONLY
+flag {
+    name: "enabled_fixed_ro"
+    namespace: "aconfig_test"
+    description: "This flag is fixed READ_ONLY + ENABLED"
+    bug: ""
+    is_fixed_read_only: true
+}
diff --git a/tools/releasetools/Android.bp b/tools/releasetools/Android.bp
index 5a7cc76..bd347a1 100644
--- a/tools/releasetools/Android.bp
+++ b/tools/releasetools/Android.bp
@@ -165,6 +165,7 @@
         "ota_utils_lib",
     ],
     required: [
+        "apexd_host",
         "brillo_update_payload",
         "checkvintf",
         "generate_gki_certificate",
@@ -344,6 +345,7 @@
     },
     srcs: [
         "merge_ota.py",
+        "ota_signing_utils.py",
     ],
     libs: [
         "ota_metadata_proto",
@@ -493,6 +495,26 @@
 }
 
 python_binary_host {
+    name: "ota_from_raw_img",
+    srcs: [
+        "ota_from_raw_img.py",
+        "ota_signing_utils.py",
+    ],
+    main: "ota_from_raw_img.py",
+    defaults: [
+        "releasetools_binary_defaults",
+    ],
+    required: [
+        "delta_generator",
+    ],
+    libs: [
+        "ota_metadata_proto",
+        "releasetools_common",
+        "ota_utils_lib",
+    ],
+}
+
+python_binary_host {
     name: "ota_package_parser",
     defaults: ["releasetools_binary_defaults"],
     srcs: [
@@ -590,6 +612,7 @@
         "sign_target_files_apks.py",
         "validate_target_files.py",
         "merge_ota.py",
+        "ota_signing_utils.py",
         ":releasetools_merge_sources",
         ":releasetools_merge_tests",
 
@@ -621,6 +644,7 @@
         },
     },
     required: [
+        "apexd_host",
         "deapexer",
     ],
 }
diff --git a/tools/releasetools/merge_ota.py b/tools/releasetools/merge_ota.py
index 441312c..24d9ea9 100644
--- a/tools/releasetools/merge_ota.py
+++ b/tools/releasetools/merge_ota.py
@@ -14,7 +14,6 @@
 
 import argparse
 import logging
-import shlex
 import struct
 import sys
 import update_payload
@@ -31,6 +30,7 @@
 
 from payload_signer import PayloadSigner
 from ota_utils import PayloadGenerator, METADATA_PROTO_NAME, FinalizeMetadata
+from ota_signing_utils import AddSigningArgumentParse
 
 logger = logging.getLogger(__name__)
 
@@ -126,7 +126,7 @@
     ExtendPartitionUpdates(output_manifest.partitions, manifest.partitions)
     try:
       MergeDynamicPartitionMetadata(
-        output_manifest.dynamic_partition_metadata, manifest.dynamic_partition_metadata)
+          output_manifest.dynamic_partition_metadata, manifest.dynamic_partition_metadata)
     except DuplicatePartitionError:
       logger.error(
           "OTA %s has duplicate partition with some of the previous OTAs", payload.name)
@@ -190,6 +190,7 @@
               f"OTA {partition_to_ota[part].name} and {payload.name} have duplicating partition {part}")
         partition_to_ota[part] = payload
 
+
 def ApexInfo(file_paths):
   if len(file_paths) > 1:
     logger.info("More than one target file specified, will ignore "
@@ -201,33 +202,19 @@
       return apex_info_bytes
   return None
 
-def ParseSignerArgs(args):
-  if args is None:
-    return None
-  return shlex.split(args)
 
 def main(argv):
   parser = argparse.ArgumentParser(description='Merge multiple partial OTAs')
   parser.add_argument('packages', type=str, nargs='+',
                       help='Paths to OTA packages to merge')
-  parser.add_argument('--package_key', type=str,
-                      help='Paths to private key for signing payload')
-  parser.add_argument('--search_path', type=str,
-                      help='Search path for framework/signapk.jar')
-  parser.add_argument('--payload_signer', type=str,
-                      help='Path to custom payload signer')
-  parser.add_argument('--payload_signer_args', type=ParseSignerArgs,
-                      help='Arguments for payload signer if necessary')
-  parser.add_argument('--payload_signer_maximum_signature_size', type=str,
-                      help='Maximum signature size (in bytes) that would be '
-                      'generated by the given payload signer')
   parser.add_argument('--output', type=str,
                       help='Paths to output merged ota', required=True)
   parser.add_argument('--metadata_ota', type=str,
                       help='Output zip will use build metadata from this OTA package, if unspecified, use the last OTA package in merge list')
-  parser.add_argument('--private_key_suffix', type=str,
-                      help='Suffix to be appended to package_key path', default=".pk8")
-  parser.add_argument('-v', action="store_true", help="Enable verbose logging", dest="verbose")
+  parser.add_argument('-v', action="store_true",
+                      help="Enable verbose logging", dest="verbose")
+  AddSigningArgumentParse(parser)
+
   parser.epilog = ('This tool can also be used to resign a regular OTA. For a single regular OTA, '
                    'apex_info.pb will be written to output. When merging multiple OTAs, '
                    'apex_info.pb will not be written.')
@@ -301,8 +288,6 @@
   return 0
 
 
-
-
 if __name__ == '__main__':
   logging.basicConfig()
   sys.exit(main(sys.argv))
diff --git a/tools/releasetools/ota_from_raw_img.py b/tools/releasetools/ota_from_raw_img.py
new file mode 100644
index 0000000..ac4f9fb
--- /dev/null
+++ b/tools/releasetools/ota_from_raw_img.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2008 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.
+
+"""
+Given a series of .img files, produces an OTA package that installs thoese images
+"""
+
+import sys
+import os
+import argparse
+import subprocess
+import tempfile
+import logging
+import zipfile
+
+import common
+from payload_signer import PayloadSigner
+from ota_utils import PayloadGenerator
+from ota_signing_utils import AddSigningArgumentParse
+
+
+logger = logging.getLogger(__name__)
+
+
+def ResolveBinaryPath(filename, search_path):
+  if not search_path:
+    return filename
+  if not os.path.exists(search_path):
+    return filename
+  path = os.path.join(search_path, "bin", filename)
+  if os.path.exists(path):
+    return path
+  path = os.path.join(search_path, filename)
+  if os.path.exists(path):
+    return path
+  return path
+
+
+def main(argv):
+  parser = argparse.ArgumentParser(
+      prog=argv[0], description="Given a series of .img files, produces a full OTA package that installs thoese images")
+  parser.add_argument("images", nargs="+", type=str,
+                      help="List of images to generate OTA")
+  parser.add_argument("--partition_names", nargs='+', type=str,
+                      help="Partition names to install the images, default to basename of the image(no file name extension)")
+  parser.add_argument('--output', type=str,
+                      help='Paths to output merged ota', required=True)
+  parser.add_argument("-v", action="store_true",
+                      help="Enable verbose logging", dest="verbose")
+  AddSigningArgumentParse(parser)
+
+  args = parser.parse_args(argv[1:])
+  if args.verbose:
+    logger.setLevel(logging.INFO)
+  logger.info(args)
+  if not args.partition_names:
+    args.partition_names = [os.path.os.path.splitext(os.path.basename(path))[
+        0] for path in args.images]
+  with tempfile.NamedTemporaryFile() as unsigned_payload:
+    cmd = [ResolveBinaryPath("delta_generator", args.search_path)]
+    cmd.append("--partition_names=" + ",".join(args.partition_names))
+    cmd.append("--new_partitions=" + ",".join(args.images))
+    cmd.append("--out_file=" + unsigned_payload.name)
+    logger.info("Running %s", cmd)
+
+    subprocess.run(cmd)
+    generator = PayloadGenerator()
+    generator.payload_file = unsigned_payload.name
+    logger.info("Payload size: %d", os.path.getsize(generator.payload_file))
+
+    # Get signing keys
+    key_passwords = common.GetKeyPasswords([args.package_key])
+
+    if args.package_key:
+      logger.info("Signing payload...")
+      # TODO: remove OPTIONS when no longer used as fallback in payload_signer
+      common.OPTIONS.payload_signer_args = None
+      common.OPTIONS.payload_signer_maximum_signature_size = None
+      signer = PayloadSigner(args.package_key, args.private_key_suffix,
+                             key_passwords[args.package_key],
+                             payload_signer=args.payload_signer,
+                             payload_signer_args=args.payload_signer_args,
+                             payload_signer_maximum_signature_size=args.payload_signer_maximum_signature_size)
+      generator.payload_file = unsigned_payload.name
+      generator.Sign(signer)
+
+    logger.info("Payload size: %d", os.path.getsize(generator.payload_file))
+
+    logger.info("Writing to %s", args.output)
+    with zipfile.ZipFile(args.output, "w") as zfp:
+      generator.WriteToZip(zfp)
+
+
+if __name__ == "__main__":
+  logging.basicConfig()
+  main(sys.argv)
diff --git a/tools/releasetools/ota_signing_utils.py b/tools/releasetools/ota_signing_utils.py
new file mode 100644
index 0000000..60c8c94
--- /dev/null
+++ b/tools/releasetools/ota_signing_utils.py
@@ -0,0 +1,38 @@
+# Copyright (C) 2022 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.
+
+import argparse
+import shlex
+
+
+def ParseSignerArgs(args):
+  if args is None:
+    return None
+  return shlex.split(args)
+
+
+def AddSigningArgumentParse(parser: argparse.ArgumentParser):
+  parser.add_argument('--package_key', type=str,
+                      help='Paths to private key for signing payload')
+  parser.add_argument('--search_path', '--path', type=str,
+                      help='Search path for framework/signapk.jar')
+  parser.add_argument('--payload_signer', type=str,
+                      help='Path to custom payload signer')
+  parser.add_argument('--payload_signer_args', type=ParseSignerArgs,
+                      help='Arguments for payload signer if necessary')
+  parser.add_argument('--payload_signer_maximum_signature_size', type=str,
+                      help='Maximum signature size (in bytes) that would be '
+                      'generated by the given payload signer')
+  parser.add_argument('--private_key_suffix', type=str,
+                      help='Suffix to be appended to package_key path', default=".pk8")
diff --git a/tools/releasetools/ota_utils.py b/tools/releasetools/ota_utils.py
index f288a9c..9b3367e 100644
--- a/tools/releasetools/ota_utils.py
+++ b/tools/releasetools/ota_utils.py
@@ -897,30 +897,7 @@
     """
     assert isinstance(payload_signer, PayloadSigner)
 
-    # 1. Generate hashes of the payload and metadata files.
-    payload_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
-    metadata_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
-    cmd = ["brillo_update_payload", "hash",
-           "--unsigned_payload", self.payload_file,
-           "--signature_size", str(payload_signer.maximum_signature_size),
-           "--metadata_hash_file", metadata_sig_file,
-           "--payload_hash_file", payload_sig_file]
-    self._Run(cmd)
-
-    # 2. Sign the hashes.
-    signed_payload_sig_file = payload_signer.SignHashFile(payload_sig_file)
-    signed_metadata_sig_file = payload_signer.SignHashFile(metadata_sig_file)
-
-    # 3. Insert the signatures back into the payload file.
-    signed_payload_file = common.MakeTempFile(prefix="signed-payload-",
-                                              suffix=".bin")
-    cmd = ["brillo_update_payload", "sign",
-           "--unsigned_payload", self.payload_file,
-           "--payload", signed_payload_file,
-           "--signature_size", str(payload_signer.maximum_signature_size),
-           "--metadata_signature_file", signed_metadata_sig_file,
-           "--payload_signature_file", signed_payload_sig_file]
-    self._Run(cmd)
+    signed_payload_file = payload_signer.SignPayload(self.payload_file)
 
     self.payload_file = signed_payload_file
 
@@ -934,9 +911,9 @@
     # 4. Dump the signed payload properties.
     properties_file = common.MakeTempFile(prefix="payload-properties-",
                                           suffix=".txt")
-    cmd = ["brillo_update_payload", "properties",
-           "--payload", self.payload_file,
-           "--properties_file", properties_file]
+    cmd = ["delta_generator",
+           "--in_file=" + self.payload_file,
+           "--properties_file=" + properties_file]
     self._Run(cmd)
 
     if self.secondary:
diff --git a/tools/releasetools/payload_signer.py b/tools/releasetools/payload_signer.py
index 9933aef..bbd2896 100644
--- a/tools/releasetools/payload_signer.py
+++ b/tools/releasetools/payload_signer.py
@@ -95,11 +95,11 @@
     # 1. Generate hashes of the payload and metadata files.
     payload_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
     metadata_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
-    cmd = ["brillo_update_payload", "hash",
-           "--unsigned_payload", unsigned_payload,
-           "--signature_size", str(self.maximum_signature_size),
-           "--metadata_hash_file", metadata_sig_file,
-           "--payload_hash_file", payload_sig_file]
+    cmd = ["delta_generator",
+           "--in_file=" + unsigned_payload,
+           "--signature_size=" + str(self.maximum_signature_size),
+           "--out_metadata_hash_file=" + metadata_sig_file,
+           "--out_hash_file=" + payload_sig_file]
     self._Run(cmd)
 
     # 2. Sign the hashes.
@@ -109,16 +109,15 @@
     # 3. Insert the signatures back into the payload file.
     signed_payload_file = common.MakeTempFile(prefix="signed-payload-",
                                               suffix=".bin")
-    cmd = ["brillo_update_payload", "sign",
-           "--unsigned_payload", unsigned_payload,
-           "--payload", signed_payload_file,
-           "--signature_size", str(self.maximum_signature_size),
-           "--metadata_signature_file", signed_metadata_sig_file,
-           "--payload_signature_file", signed_payload_sig_file]
+    cmd = ["delta_generator",
+           "--in_file=" + unsigned_payload,
+           "--out_file=" + signed_payload_file,
+           "--signature_size=" + str(self.maximum_signature_size),
+           "--metadata_signature_file=" + signed_metadata_sig_file,
+           "--payload_signature_file=" + signed_payload_sig_file]
     self._Run(cmd)
     return signed_payload_file
 
-
   def SignHashFile(self, in_file):
     """Signs the given input file. Returns the output filename."""
     out_file = common.MakeTempFile(prefix="signed-", suffix=".bin")
diff --git a/tools/zipalign/Android.bp b/tools/zipalign/Android.bp
index 0e1d58e..8be7e25 100644
--- a/tools/zipalign/Android.bp
+++ b/tools/zipalign/Android.bp
@@ -70,6 +70,7 @@
         "libgmock",
     ],
     data: [
+         "tests/data/apkWithUncompressedSharedLibs.zip",
          "tests/data/archiveWithOneDirectoryEntry.zip",
          "tests/data/diffOrders.zip",
          "tests/data/holes.zip",
diff --git a/tools/zipalign/ZipAlign.cpp b/tools/zipalign/ZipAlign.cpp
index 23840e3..f32f90b 100644
--- a/tools/zipalign/ZipAlign.cpp
+++ b/tools/zipalign/ZipAlign.cpp
@@ -17,6 +17,7 @@
 #include "ZipFile.h"
 
 #include <stdio.h>
+#include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -36,17 +37,14 @@
 }
 
 static int getAlignment(bool pageAlignSharedLibs, int defaultAlignment,
-    ZipEntry* pEntry) {
-
-    static const int kPageAlignment = 4096;
-
+    ZipEntry* pEntry, int pageSize) {
     if (!pageAlignSharedLibs) {
         return defaultAlignment;
     }
 
     const char* ext = strrchr(pEntry->getFileName(), '.');
     if (ext && strcmp(ext, ".so") == 0) {
-        return kPageAlignment;
+        return pageSize;
     }
 
     return defaultAlignment;
@@ -56,7 +54,7 @@
  * Copy all entries from "pZin" to "pZout", aligning as needed.
  */
 static int copyAndAlign(ZipFile* pZin, ZipFile* pZout, int alignment, bool zopfli,
-    bool pageAlignSharedLibs)
+    bool pageAlignSharedLibs, int pageSize)
 {
     int numEntries = pZin->getNumEntries();
     ZipEntry* pEntry;
@@ -84,7 +82,8 @@
                 status = pZout->add(pZin, pEntry, padding, &pNewEntry);
             }
         } else {
-            const int alignTo = getAlignment(pageAlignSharedLibs, alignment, pEntry);
+            const int alignTo = getAlignment(pageAlignSharedLibs, alignment, pEntry,
+                                             pageSize);
 
             //printf("--- %s: orig at %ld(+%d) len=%ld, adding pad=%d\n",
             //    pEntry->getFileName(), (long) pEntry->getFileOffset(),
@@ -107,7 +106,7 @@
  * output file exists and "force" wasn't specified.
  */
 int process(const char* inFileName, const char* outFileName,
-    int alignment, bool force, bool zopfli, bool pageAlignSharedLibs)
+    int alignment, bool force, bool zopfli, bool pageAlignSharedLibs, int pageSize)
 {
     ZipFile zin, zout;
 
@@ -127,7 +126,7 @@
     }
 
     if (zin.open(inFileName, ZipFile::kOpenReadOnly) != OK) {
-        fprintf(stderr, "Unable to open '%s' as zip archive\n", inFileName);
+        fprintf(stderr, "Unable to open '%s' as zip archive: %s\n", inFileName, strerror(errno));
         return 1;
     }
     if (zout.open(outFileName,
@@ -138,7 +137,8 @@
         return 1;
     }
 
-    int result = copyAndAlign(&zin, &zout, alignment, zopfli, pageAlignSharedLibs);
+    int result = copyAndAlign(&zin, &zout, alignment, zopfli, pageAlignSharedLibs,
+                              pageSize);
     if (result != 0) {
         printf("zipalign: failed rewriting '%s' to '%s'\n",
             inFileName, outFileName);
@@ -150,7 +150,7 @@
  * Verify the alignment of a zip archive.
  */
 int verify(const char* fileName, int alignment, bool verbose,
-    bool pageAlignSharedLibs)
+    bool pageAlignSharedLibs, int pageSize)
 {
     ZipFile zipFile;
     bool foundBad = false;
@@ -181,7 +181,8 @@
             continue;
        } else {
             off_t offset = pEntry->getFileOffset();
-            const int alignTo = getAlignment(pageAlignSharedLibs, alignment, pEntry);
+            const int alignTo = getAlignment(pageAlignSharedLibs, alignment, pEntry,
+                                             pageSize);
             if ((offset % alignTo) != 0) {
                 if (verbose) {
                     printf("%8jd %s (BAD - %jd)\n",
diff --git a/tools/zipalign/ZipAlignMain.cpp b/tools/zipalign/ZipAlignMain.cpp
index 53fc8d4..2f24403 100644
--- a/tools/zipalign/ZipAlignMain.cpp
+++ b/tools/zipalign/ZipAlignMain.cpp
@@ -34,15 +34,18 @@
     fprintf(stderr, "Zip alignment utility\n");
     fprintf(stderr, "Copyright (C) 2009 The Android Open Source Project\n\n");
     fprintf(stderr,
-        "Usage: zipalign [-f] [-p] [-v] [-z] <align> infile.zip outfile.zip\n"
-        "       zipalign -c [-p] [-v] <align> infile.zip\n\n" );
+        "Usage: zipalign [-f] [-p] [-P <pagesize_kb>] [-v] [-z] <align> infile.zip outfile.zip\n"
+        "       zipalign -c [-p] [-P <pagesize_kb>] [-v] <align> infile.zip\n\n" );
     fprintf(stderr,
         "  <align>: alignment in bytes, e.g. '4' provides 32-bit alignment\n");
     fprintf(stderr, "  -c: check alignment only (does not modify file)\n");
     fprintf(stderr, "  -f: overwrite existing outfile.zip\n");
-    fprintf(stderr, "  -p: page-align uncompressed .so files\n");
+    fprintf(stderr, "  -p: 4kb page-align uncompressed .so files\n");
     fprintf(stderr, "  -v: verbose output\n");
     fprintf(stderr, "  -z: recompress using Zopfli\n");
+    fprintf(stderr, "  -P <pagesize_kb>: Align uncompressed .so files to the specified\n");
+    fprintf(stderr, "                    page size. Valid values for <pagesize_kb> are 4, 16\n");
+    fprintf(stderr, "                    and 64. '-P' cannot be used in combination with '-p'.\n");
 }
 
 
@@ -57,12 +60,16 @@
     bool verbose = false;
     bool zopfli = false;
     bool pageAlignSharedLibs = false;
+    int pageSize = 4096;
+    bool legacyPageAlignmentFlag = false;   // -p
+    bool pageAlignmentFlag = false;         // -P <pagesize_kb>
     int result = 1;
     int alignment;
     char* endp;
 
     int opt;
-    while ((opt = getopt(argc, argv, "fcpvz")) != -1) {
+
+    while ((opt = getopt(argc, argv, "fcpvzP:")) != -1) {
         switch (opt) {
         case 'c':
             check = true;
@@ -77,7 +84,29 @@
             zopfli = true;
             break;
         case 'p':
+            legacyPageAlignmentFlag = true;
             pageAlignSharedLibs = true;
+            pageSize = 4096;
+            break;
+        case 'P':
+            pageAlignmentFlag = true;
+            pageAlignSharedLibs = true;
+
+            if (!optarg) {
+                fprintf(stderr, "ERROR: -P requires an argument\n");
+                wantUsage = true;
+                goto bail;
+            }
+
+            pageSize = atoi(optarg);
+            if (pageSize != 4 && pageSize != 16 && pageSize != 64) {
+                fprintf(stderr, "ERROR: Invalid argument for -P: %s\n", optarg);
+                wantUsage = true;
+                goto bail;
+            }
+
+            pageSize *= 1024;  // Convert from kB to bytes.
+
             break;
         default:
             fprintf(stderr, "ERROR: unknown flag -%c\n", opt);
@@ -86,6 +115,13 @@
         }
     }
 
+    if (legacyPageAlignmentFlag && pageAlignmentFlag) {
+            fprintf(stderr, "ERROR: Invalid options: '-P <pagesize_kb>' and '-p'"
+                            "cannot be used in combination.\n");
+            wantUsage = true;
+            goto bail;
+    }
+
     if (!((check && (argc - optind) == 2) || (!check && (argc - optind) == 3))) {
         wantUsage = true;
         goto bail;
@@ -100,14 +136,15 @@
 
     if (check) {
         /* check existing archive for correct alignment */
-        result = verify(argv[optind + 1], alignment, verbose, pageAlignSharedLibs);
+        result = verify(argv[optind + 1], alignment, verbose, pageAlignSharedLibs, pageSize);
     } else {
         /* create the new archive */
-        result = process(argv[optind + 1], argv[optind + 2], alignment, force, zopfli, pageAlignSharedLibs);
+        result = process(argv[optind + 1], argv[optind + 2], alignment, force, zopfli,
+                         pageAlignSharedLibs, pageSize);
 
         /* trust, but verify */
         if (result == 0) {
-            result = verify(argv[optind + 2], alignment, verbose, pageAlignSharedLibs);
+            result = verify(argv[optind + 2], alignment, verbose, pageAlignSharedLibs, pageSize);
         }
     }
 
diff --git a/tools/zipalign/include/ZipAlign.h b/tools/zipalign/include/ZipAlign.h
index ab36086..85dda14 100644
--- a/tools/zipalign/include/ZipAlign.h
+++ b/tools/zipalign/include/ZipAlign.h
@@ -25,24 +25,28 @@
  * - force  : Overwrite output if it exists, fail otherwise.
  * - zopfli : Recompress compressed entries with more efficient algorithm.
  *            Copy compressed entries as-is, and unaligned, otherwise.
- * - pageAlignSharedLibs: Align .so files to 4096 and other files to
+ * - pageAlignSharedLibs: Align .so files to @pageSize and other files to
  *   alignTo, or all files to alignTo if false..
+ * - pageSize: Specifies the page size of the target device. This is used
+ *             to correctly page-align shared libraries.
  *
  * Returns 0 on success.
  */
 int process(const char* input, const char* output, int alignTo, bool force,
-    bool zopfli, bool pageAlignSharedLibs);
+    bool zopfli, bool pageAlignSharedLibs, int pageSize);
 
 /*
  * Verify the alignment of a zip archive.
  * - alignTo: Alignment (in bytes) for uncompressed entries.
- * - pageAlignSharedLibs: Align .so files to 4096 and other files to
+ * - pageAlignSharedLibs: Align .so files to @pageSize and other files to
  *   alignTo, or all files to alignTo if false..
+ * - pageSize: Specifies the page size of the target device. This is used
+ *             to correctly page-align shared libraries.
  *
  * Returns 0 on success.
  */
 int verify(const char* fileName, int alignTo, bool verbose,
-    bool pageAlignSharedLibs);
+    bool pageAlignSharedLibs, int pageSize);
 
 } // namespace android
 
diff --git a/tools/zipalign/tests/data/apkWithUncompressedSharedLibs.zip b/tools/zipalign/tests/data/apkWithUncompressedSharedLibs.zip
new file mode 100644
index 0000000..930e3b5
--- /dev/null
+++ b/tools/zipalign/tests/data/apkWithUncompressedSharedLibs.zip
Binary files differ
diff --git a/tools/zipalign/tests/src/align_test.cpp b/tools/zipalign/tests/src/align_test.cpp
index a8433fa..07ad7cc 100644
--- a/tools/zipalign/tests/src/align_test.cpp
+++ b/tools/zipalign/tests/src/align_test.cpp
@@ -48,11 +48,12 @@
 TEST(Align, Unaligned) {
   const std::string src = GetTestPath("unaligned.zip");
   const std::string dst = GetTempPath("unaligned_out.zip");
+  int pageSize = 4096;
 
-  int processed = process(src.c_str(), dst.c_str(), 4, true, false, 4096);
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, false, pageSize);
   ASSERT_EQ(0, processed);
 
-  int verified = verify(dst.c_str(), 4, true, false);
+  int verified = verify(dst.c_str(), 4, true, false, pageSize);
   ASSERT_EQ(0, verified);
 }
 
@@ -60,18 +61,19 @@
   const std::string src = GetTestPath("unaligned.zip");
   const std::string tmp = GetTempPath("da_aligned.zip");
   const std::string dst = GetTempPath("da_d_aligner.zip");
+  int pageSize = 4096;
 
-  int processed = process(src.c_str(), tmp.c_str(), 4, true, false, 4096);
+  int processed = process(src.c_str(), tmp.c_str(), 4, true, false, false, pageSize);
   ASSERT_EQ(0, processed);
 
-  int verified = verify(tmp.c_str(), 4, true, false);
+  int verified = verify(tmp.c_str(), 4, true, false, pageSize);
   ASSERT_EQ(0, verified);
 
   // Align the result of the previous run. Essentially double aligning.
-  processed = process(tmp.c_str(), dst.c_str(), 4, true, false, 4096);
+  processed = process(tmp.c_str(), dst.c_str(), 4, true, false, false, pageSize);
   ASSERT_EQ(0, processed);
 
-  verified = verify(dst.c_str(), 4, true, false);
+  verified = verify(dst.c_str(), 4, true, false, pageSize);
   ASSERT_EQ(0, verified);
 
   // Nothing should have changed between tmp and dst.
@@ -90,11 +92,12 @@
 TEST(Align, Holes) {
   const std::string src = GetTestPath("holes.zip");
   const std::string dst = GetTempPath("holes_out.zip");
+  int pageSize = 4096;
 
-  int processed = process(src.c_str(), dst.c_str(), 4, true, false, 4096);
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, true, pageSize);
   ASSERT_EQ(0, processed);
 
-  int verified = verify(dst.c_str(), 4, false, true);
+  int verified = verify(dst.c_str(), 4, false, true, pageSize);
   ASSERT_EQ(0, verified);
 }
 
@@ -102,28 +105,85 @@
 TEST(Align, DifferenteOrders) {
   const std::string src = GetTestPath("diffOrders.zip");
   const std::string dst = GetTempPath("diffOrders_out.zip");
+  int pageSize = 4096;
 
-  int processed = process(src.c_str(), dst.c_str(), 4, true, false, 4096);
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, true, pageSize);
   ASSERT_EQ(0, processed);
 
-  int verified = verify(dst.c_str(), 4, false, true);
+  int verified = verify(dst.c_str(), 4, false, true, pageSize);
   ASSERT_EQ(0, verified);
 }
 
 TEST(Align, DirectoryEntryDoNotRequireAlignment) {
   const std::string src = GetTestPath("archiveWithOneDirectoryEntry.zip");
-  int verified = verify(src.c_str(), 4, false, true);
+  int pageSize = 4096;
+  int verified = verify(src.c_str(), 4, false, true, pageSize);
   ASSERT_EQ(0, verified);
 }
 
 TEST(Align, DirectoryEntry) {
   const std::string src = GetTestPath("archiveWithOneDirectoryEntry.zip");
   const std::string dst = GetTempPath("archiveWithOneDirectoryEntry_out.zip");
+  int pageSize = 4096;
 
-  int processed = process(src.c_str(), dst.c_str(), 4, true, false, 4096);
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, true, pageSize);
   ASSERT_EQ(0, processed);
   ASSERT_EQ(true, sameContent(src, dst));
 
-  int verified = verify(dst.c_str(), 4, false, true);
+  int verified = verify(dst.c_str(), 4, false, true, pageSize);
+  ASSERT_EQ(0, verified);
+}
+
+class UncompressedSharedLibsTest : public ::testing::Test {
+  protected:
+    static void SetUpTestSuite() {
+      src = GetTestPath("apkWithUncompressedSharedLibs.zip");
+      dst = GetTempPath("apkWithUncompressedSharedLibs_out.zip");
+    }
+
+    static std::string src;
+    static std::string dst;
+};
+
+std::string UncompressedSharedLibsTest::src;
+std::string UncompressedSharedLibsTest::dst;
+
+TEST_F(UncompressedSharedLibsTest, Unaligned) {
+  int pageSize = 4096;
+
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, false, pageSize);
+  ASSERT_EQ(0, processed);
+
+  int verified = verify(dst.c_str(), 4, true, true, pageSize);
+  ASSERT_NE(0, verified); // .so's not page-aligned
+}
+
+TEST_F(UncompressedSharedLibsTest, AlignedPageSize4kB) {
+  int pageSize = 4096;
+
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, true, pageSize);
+  ASSERT_EQ(0, processed);
+
+  int verified = verify(dst.c_str(), 4, true, true, pageSize);
+  ASSERT_EQ(0, verified);
+}
+
+TEST_F(UncompressedSharedLibsTest, AlignedPageSize16kB) {
+  int pageSize = 16384;
+
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, true, pageSize);
+  ASSERT_EQ(0, processed);
+
+  int verified = verify(dst.c_str(), 4, true, true, pageSize);
+  ASSERT_EQ(0, verified);
+}
+
+TEST_F(UncompressedSharedLibsTest, AlignedPageSize64kB) {
+  int pageSize = 65536;
+
+  int processed = process(src.c_str(), dst.c_str(), 4, true, false, true, pageSize);
+  ASSERT_EQ(0, processed);
+
+  int verified = verify(dst.c_str(), 4, true, true, pageSize);
   ASSERT_EQ(0, verified);
 }