diff --git a/core/OWNERS b/core/OWNERS
index d48ceab..762d2a7 100644
--- a/core/OWNERS
+++ b/core/OWNERS
@@ -1,4 +1,5 @@
-per-file *dex_preopt*.* = ngeoffray@google.com,skvadrik@google.com
+per-file *dex_preopt*.* = jiakaiz@google.com,ngeoffray@google.com,skvadrik@google.com
+per-file art_*.* = jiakaiz@google.com,ngeoffray@google.com,skvadrik@google.com
 per-file verify_uses_libraries.sh = ngeoffray@google.com,skvadrik@google.com
 
 # For global Proguard rules
diff --git a/core/art_config.mk b/core/art_config.mk
new file mode 100644
index 0000000..1ea05db
--- /dev/null
+++ b/core/art_config.mk
@@ -0,0 +1,46 @@
+# ART configuration that has to be determined after product config is resolved.
+#
+# Inputs:
+# PRODUCT_ENABLE_UFFD_GC: See comments in build/make/core/product.mk.
+# OVERRIDE_ENABLE_UFFD_GC: Overrides PRODUCT_ENABLE_UFFD_GC. Can be passed from the commandline for
+# debugging purposes.
+# BOARD_API_LEVEL: See comments in build/make/core/main.mk.
+# BOARD_SHIPPING_API_LEVEL: See comments in build/make/core/main.mk.
+# PRODUCT_SHIPPING_API_LEVEL: See comments in build/make/core/product.mk.
+#
+# Outputs:
+# ENABLE_UFFD_GC: Whether to use userfaultfd GC.
+
+config_enable_uffd_gc := \
+  $(firstword $(OVERRIDE_ENABLE_UFFD_GC) $(PRODUCT_ENABLE_UFFD_GC))
+
+ifeq (,$(filter-out default,$(config_enable_uffd_gc)))
+  ENABLE_UFFD_GC := true
+
+  # Disable userfaultfd GC if the device doesn't support it (i.e., if
+  # `min(ro.board.api_level ?? ro.board.first_api_level ?? MAX_VALUE,
+  #      ro.product.first_api_level ?? ro.build.version.sdk ?? MAX_VALUE) < 31`)
+  # This logic aligns with how `ro.vendor.api_level` is calculated in
+  # `system/core/init/property_service.cpp`.
+  # We omit the check on `ro.build.version.sdk` here because we are on the latest build system.
+  board_api_level := $(firstword $(BOARD_API_LEVEL) $(BOARD_SHIPPING_API_LEVEL))
+  ifneq (,$(board_api_level))
+    ifeq (true,$(call math_lt,$(board_api_level),31))
+      ENABLE_UFFD_GC := false
+    endif
+  endif
+
+  ifneq (,$(PRODUCT_SHIPPING_API_LEVEL))
+    ifeq (true,$(call math_lt,$(PRODUCT_SHIPPING_API_LEVEL),31))
+      ENABLE_UFFD_GC := false
+    endif
+  endif
+else ifeq (true,$(config_enable_uffd_gc))
+  ENABLE_UFFD_GC := true
+else ifeq (false,$(config_enable_uffd_gc))
+  ENABLE_UFFD_GC := false
+else
+  $(error Unknown PRODUCT_ENABLE_UFFD_GC value: $(config_enable_uffd_gc))
+endif
+
+ADDITIONAL_PRODUCT_PROPERTIES += ro.dalvik.vm.enable_uffd_gc=$(ENABLE_UFFD_GC)
diff --git a/core/dex_preopt_config.mk b/core/dex_preopt_config.mk
index c11b7f4..e36e2eb 100644
--- a/core/dex_preopt_config.mk
+++ b/core/dex_preopt_config.mk
@@ -130,6 +130,7 @@
   $(call add_json_str,  Dex2oatXmx,                              $(DEX2OAT_XMX))
   $(call add_json_str,  Dex2oatXms,                              $(DEX2OAT_XMS))
   $(call add_json_str,  EmptyDirectory,                          $(OUT_DIR)/empty)
+  $(call add_json_bool, EnableUffdGc,                            $(filter true,$(ENABLE_UFFD_GC)))
 
 ifdef TARGET_ARCH
   $(call add_json_map,  CpuVariant)
diff --git a/core/java_host_unit_test_config_template.xml b/core/java_host_unit_test_config_template.xml
index d8795f9..5d8b254 100644
--- a/core/java_host_unit_test_config_template.xml
+++ b/core/java_host_unit_test_config_template.xml
@@ -23,5 +23,14 @@
 
     <test class="com.android.tradefed.testtype.IsolatedHostTest" >
         <option name="jar" value="{MODULE}.jar" />
+        <option name="java-flags" value="--add-modules=jdk.compiler"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED"/>
+        <option name="java-flags" value="--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED"/>
     </test>
 </configuration>
diff --git a/core/main.mk b/core/main.mk
index 2e39601..0453cda 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -493,6 +493,8 @@
 # Typical build; include any Android.mk files we can find.
 #
 
+include $(BUILD_SYSTEM)/art_config.mk
+
 # Bring in dex_preopt.mk
 # This creates some modules so it needs to be included after
 # should-install-to-system is defined (in order for base_rules.mk to function
diff --git a/core/product.mk b/core/product.mk
index dcfdf1f..4c642b8 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -370,6 +370,18 @@
 # If true, installs a full version of com.android.virt APEX.
 _product_single_value_vars += PRODUCT_AVF_ENABLED
 
+# Whether to use userfaultfd GC.
+# Possible values are:
+# - "default" or empty: both the build system and the runtime determine whether to use userfaultfd
+#   GC based on the vendor API level
+# - "true": forces the build system to use userfaultfd GC regardless of the vendor API level; the
+#   runtime determines whether to use userfaultfd GC based on the kernel support. Note that the
+#   device may have to re-compile everything on the first boot if the kernel doesn't support
+#   userfaultfd
+# - "false": disallows the build system and the runtime to use userfaultfd GC even if the device
+#   supports it
+_product_single_value_vars += PRODUCT_ENABLE_UFFD_GC
+
 .KATI_READONLY := _product_single_value_vars _product_list_vars
 _product_var_list :=$= $(_product_single_value_vars) $(_product_list_vars)
 
diff --git a/core/soong_config.mk b/core/soong_config.mk
index b000df6..7d3ae23 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -9,6 +9,7 @@
 endif
 endif
 
+include $(BUILD_SYSTEM)/art_config.mk
 include $(BUILD_SYSTEM)/dex_preopt_config.mk
 
 ifeq ($(WRITE_SOONG_VARIABLES),true)
diff --git a/envsetup.sh b/envsetup.sh
index 4c1aeaa..3709999 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -35,6 +35,7 @@
 - rsgrep:     Greps on all local Rust files.
 - sepgrep:    Greps on all local sepolicy files.
 - sgrep:      Greps on all local source files.
+- pygrep:     Greps on all local Python files.
 - godir:      Go to the directory containing a file.
 - allmod:     List all modules.
 - gomod:      Go to the directory containing a module.
@@ -1226,6 +1227,12 @@
         -exec grep --color -n "$@" {} +
 }
 
+function pygrep()
+{
+    find . -name .repo -prune -o -name .git -prune -o -name out -prune -o -type f -name "*\.py" \
+        -exec grep --color -n "$@" {} +
+}
+
 case `uname -s` in
     Darwin)
         function mgrep()
diff --git a/finalize-step-1-for-build-target.sh b/finalize-step-1-for-build-target.sh
new file mode 100755
index 0000000..843c142
--- /dev/null
+++ b/finalize-step-1-for-build-target.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+# Continuous Integration script for *-finalization-1 branches.
+# Reverts previous finalization script commits and runs local build.
+
+function revert_to_unfinalized_state() {
+    repo forall -c '\
+        git checkout . ; git revert --abort ; git clean -fdx ;\
+        git checkout @ ; git branch fina-step1 -D ; git reset --hard; \
+        repo start fina-step1 ; git checkout @ ; git b fina-step1 -D ;\
+        baselineHash="$(git log --format=%H --no-merges --max-count=1 --grep ^FINALIZATION_STEP_1_BASELINE_COMMIT)" ;\
+        if [[ $baselineHash ]]; then
+          previousHash="$(git log --format=%H --no-merges --max-count=100 --grep ^FINALIZATION_STEP_1_SCRIPT_COMMIT $baselineHash..HEAD | tr \n \040)" ;\
+        else
+          previousHash="$(git log --format=%H --no-merges --max-count=100 --grep ^FINALIZATION_STEP_1_SCRIPT_COMMIT | tr \n \040)" ;\
+        fi ; \
+        if [[ $previousHash ]]; then git revert --no-commit --strategy=ort --strategy-option=ours $previousHash ; fi ;'
+}
+
+function finalize_step_1_main() {
+    local top="$(dirname "$0")"/../..
+    local m="$top/build/soong/soong_ui.bash --make-mode TARGET_PRODUCT=aosp_arm64 TARGET_BUILD_VARIANT=userdebug"
+
+    revert_to_unfinalized_state
+
+    set -ex
+
+    # vndk etc finalization
+    source $top/build/make/finalize-aidl-vndk-sdk-resources.sh
+
+    # build to confirm everything is OK
+    AIDL_FROZEN_REL=true $m
+}
+
+finalize_step_1_main
diff --git a/target/product/aosp_riscv64.mk b/target/product/aosp_riscv64.mk
index 023317b..436ff97 100644
--- a/target/product/aosp_riscv64.mk
+++ b/target/product/aosp_riscv64.mk
@@ -62,6 +62,7 @@
 # just the modules that work for riscv64.
 PRODUCT_PACKAGES := \
   init.environ.rc \
+  init_first_stage \
   init_system \
   linker \
   shell_and_utilities \
diff --git a/target/product/default_art_config.mk b/target/product/default_art_config.mk
index 20d2865..4e75679 100644
--- a/target/product/default_art_config.mk
+++ b/target/product/default_art_config.mk
@@ -113,3 +113,5 @@
     dalvik.vm.image-dex2oat-Xmx=64m \
     dalvik.vm.dex2oat-Xms=64m \
     dalvik.vm.dex2oat-Xmx=512m \
+
+PRODUCT_ENABLE_UFFD_GC := false  # TODO(jiakaiz): Change this to "default".
diff --git a/target/product/gsi/current.txt b/target/product/gsi/current.txt
index 56a9d8a..24005d9 100644
--- a/target/product/gsi/current.txt
+++ b/target/product/gsi/current.txt
@@ -21,7 +21,6 @@
 LLNDK: libvulkan.so
 VNDK-SP: android.hardware.common-V2-ndk.so
 VNDK-SP: android.hardware.common.fmq-V1-ndk.so
-VNDK-SP: android.hardware.graphics.allocator-V1-ndk.so
 VNDK-SP: android.hardware.graphics.common-V3-ndk.so
 VNDK-SP: android.hardware.graphics.common@1.0.so
 VNDK-SP: android.hardware.graphics.common@1.1.so
@@ -31,6 +30,7 @@
 VNDK-SP: android.hardware.graphics.mapper@2.1.so
 VNDK-SP: android.hardware.graphics.mapper@3.0.so
 VNDK-SP: android.hardware.graphics.mapper@4.0.so
+VNDK-SP: android.hardware.graphics.allocator-V1-ndk.so
 VNDK-SP: android.hardware.renderscript@1.0.so
 VNDK-SP: android.hidl.memory.token@1.0.so
 VNDK-SP: android.hidl.memory@1.0-impl.so