diff --git a/core/Makefile b/core/Makefile
index 2d56edb..a6959fa 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -2327,14 +2327,14 @@
 $(error MTD device is no longer supported and thus BOARD_NAND_SPARE_SIZE is deprecated.)
 endif
 
-ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
+
 # -----------------------------------------------------------------
 # the debug ramdisk, which is the original ramdisk plus additional
 # files: force_debuggable, adb_debug.prop and userdebug sepolicy.
 # When /force_debuggable is present, /init will load userdebug sepolicy
 # and property files to allow adb root, if the device is unlocked.
+ifneq ($(BUILDING_DEBUG_BOOT_IMAGE)$(BUILDING_DEBUG_VENDOR_BOOT_IMAGE),)
 
-ifdef BUILDING_RAMDISK_IMAGE
 BUILT_DEBUG_RAMDISK_TARGET := $(PRODUCT_OUT)/ramdisk-debug.img
 INSTALLED_DEBUG_RAMDISK_TARGET := $(BUILT_DEBUG_RAMDISK_TARGET)
 
@@ -2391,15 +2391,15 @@
 	touch $(TARGET_DEBUG_RAMDISK_OUT)/force_debuggable
 	$(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_DEBUG_RAMDISK_OUT) $(PRIVATE_ADDITIONAL_DIR) | $(COMPRESSION_COMMAND) > $(INSTALLED_DEBUG_RAMDISK_TARGET)
 
-endif # BUILDING_RAMDISK_IMAGE
+endif # BUILDING_DEBUG_BOOT_IMAGE || BUILDING_DEBUG_VENDOR_BOOT_IMAGE
 
 # -----------------------------------------------------------------
 # the boot-debug.img, which is the kernel plus ramdisk-debug.img
 #
 # Note: it's intentional to skip signing for boot-debug.img, because it
 # can only be used if the device is unlocked with verification error.
-ifneq ($(INSTALLED_BOOTIMAGE_TARGET),)
-ifneq ($(strip $(TARGET_NO_KERNEL)),true)
+ifdef BUILDING_DEBUG_BOOT_IMAGE
+
 ifneq ($(strip $(BOARD_KERNEL_BINARIES)),)
   INSTALLED_DEBUG_BOOTIMAGE_TARGET := $(foreach k,$(subst kernel,boot-debug,$(BOARD_KERNEL_BINARIES)), \
          $(PRODUCT_OUT)/$(k).img)
@@ -2454,15 +2454,13 @@
 	echo "make $@: ignoring dependencies"
 	$(foreach b,$(INSTALLED_DEBUG_BOOTIMAGE_TARGET),$(call build-debug-bootimage-target,$b))
 
-endif # TARGET_NO_KERNEL
-endif # INSTALLED_BOOTIMAGE_TARGET
+endif # BUILDING_DEBUG_BOOT_IMAGE
 
-ifeq ($(BUILDING_VENDOR_BOOT_IMAGE),true)
-ifeq ($(BUILDING_RAMDISK_IMAGE),true)
 # -----------------------------------------------------------------
 # vendor debug ramdisk
 # Combines vendor ramdisk files and debug ramdisk files to build the vendor debug ramdisk.
-#
+ifdef BUILDING_DEBUG_VENDOR_BOOT_IMAGE
+
 INTERNAL_VENDOR_DEBUG_RAMDISK_FILES := $(filter $(TARGET_VENDOR_DEBUG_RAMDISK_OUT)/%, \
     $(ALL_GENERATED_SOURCES) \
     $(ALL_DEFAULT_INSTALLED_MODULES))
@@ -2534,14 +2532,13 @@
 	$(call assert-max-image-size,$@,$(BOARD_VENDOR_BOOTIMAGE_PARTITION_SIZE))
 	$(if $(BOARD_AVB_VENDOR_BOOT_KEY_PATH),$(call test-key-sign-vendor-bootimage,$@))
 
-endif # BUILDING_RAMDISK_IMAGE
-endif # BUILDING_VENDOR_BOOT_IMAGE
+endif # BUILDING_DEBUG_VENDOR_BOOT_IMAGE
 
 # -----------------------------------------------------------------
 # The test harness ramdisk, which is based off debug_ramdisk, plus a
 # few additional test-harness-specific properties in adb_debug.prop.
+ifneq ($(BUILDING_DEBUG_BOOT_IMAGE)$(BUILDING_DEBUG_VENDOR_BOOT_IMAGE),)
 
-ifdef BUILDING_RAMDISK_IMAGE
 BUILT_TEST_HARNESS_RAMDISK_TARGET := $(PRODUCT_OUT)/ramdisk-test-harness.img
 INSTALLED_TEST_HARNESS_RAMDISK_TARGET := $(BUILT_TEST_HARNESS_RAMDISK_TARGET)
 
@@ -2594,15 +2591,14 @@
 	$(call append-test-harness-props,$(ADDITIONAL_TEST_HARNESS_PROPERTIES),$(TEST_HARNESS_PROP_TARGET))
 	$(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_TEST_HARNESS_RAMDISK_OUT) $(PRIVATE_ADDITIONAL_DIR) | $(COMPRESSION_COMMAND) > $(INSTALLED_TEST_HARNESS_RAMDISK_TARGET)
 
-endif # BUILDING_RAMDISK_IMAGE
+endif # BUILDING_DEBUG_BOOT_IMAGE || BUILDING_DEBUG_VENDOR_BOOT_IMAGE
 
 # -----------------------------------------------------------------
 # the boot-test-harness.img, which is the kernel plus ramdisk-test-harness.img
 #
 # Note: it's intentional to skip signing for boot-test-harness.img, because it
 # can only be used if the device is unlocked with verification error.
-ifneq ($(INSTALLED_BOOTIMAGE_TARGET),)
-ifneq ($(strip $(TARGET_NO_KERNEL)),true)
+ifdef BUILDING_DEBUG_BOOT_IMAGE
 
 ifneq ($(strip $(BOARD_KERNEL_BINARIES)),)
   INSTALLED_TEST_HARNESS_BOOTIMAGE_TARGET := $(foreach k,$(subst kernel,boot-test-harness,$(BOARD_KERNEL_BINARIES)), \
@@ -2641,15 +2637,12 @@
 	echo "make $@: ignoring dependencies"
 	$(foreach b,$(INSTALLED_TEST_HARNESS_BOOTIMAGE_TARGET),$(call build-boot-test-harness-target,$b))
 
-endif # TARGET_NO_KERNEL
-endif # INSTALLED_BOOTIMAGE_TARGET
-endif # BOARD_BUILD_SYSTEM_ROOT_IMAGE is not true
+endif # BUILDING_DEBUG_BOOT_IMAGE
 
-ifeq ($(BUILDING_VENDOR_BOOT_IMAGE),true)
-ifeq ($(BUILDING_RAMDISK_IMAGE),true)
 # -----------------------------------------------------------------
 # vendor test harness ramdisk, which is a vendor ramdisk combined with
 # a test harness ramdisk.
+ifdef BUILDING_DEBUG_VENDOR_BOOT_IMAGE
 
 INTERNAL_VENDOR_TEST_HARNESS_RAMDISK_TARGET := $(call intermediates-dir-for,PACKAGING,vendor_boot-test-harness)/vendor_ramdisk-test-harness.cpio$(RAMDISK_EXT)
 
@@ -2684,8 +2677,8 @@
 	$(call assert-max-image-size,$@,$(BOARD_VENDOR_BOOTIMAGE_PARTITION_SIZE))
 	$(if $(BOARD_AVB_VENDOR_BOOT_KEY_PATH),$(call test-key-sign-vendor-bootimage,$@))
 
-endif # BUILDING_RAMDISK_IMAGE
-endif # BUILDING_VENDOR_BOOT_IMAGE
+endif # BUILDING_DEBUG_VENDOR_BOOT_IMAGE
+
 
 # Creates a compatibility symlink between two partitions, e.g. /system/vendor to /vendor
 # $1: from location (e.g $(TARGET_OUT)/vendor)
diff --git a/core/android_soong_config_vars.mk b/core/android_soong_config_vars.mk
index c6f4d68..2e33998 100644
--- a/core/android_soong_config_vars.mk
+++ b/core/android_soong_config_vars.mk
@@ -28,6 +28,7 @@
 
 $(call add_soong_config_var,ANDROID,TARGET_ENABLE_MEDIADRM_64)
 $(call add_soong_config_var,ANDROID,BOARD_USES_ODMIMAGE)
+$(call add_soong_config_var,ANDROID,PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT)
 
 ifeq (,$(findstring com.google.android.conscrypt,$(PRODUCT_PACKAGES)))
   # Prebuilt module SDKs require prebuilt modules to work, and currently
diff --git a/core/board_config.mk b/core/board_config.mk
index 1b08f9a..ea6ec1e 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -439,6 +439,86 @@
 endif
 .KATI_READONLY := BUILDING_RAMDISK_IMAGE
 
+# Are we building a debug vendor_boot image
+BUILDING_DEBUG_VENDOR_BOOT_IMAGE :=
+# Can't build vendor_boot-debug.img if BOARD_BUILD_SYSTEM_ROOT_IMAGE is true,
+# because building debug vendor_boot image requires a ramdisk.
+ifeq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
+  ifeq ($(PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE is true, but so is BOARD_BUILD_SYSTEM_ROOT_IMAGE. \
+      Skip building the debug vendor_boot image.)
+  endif
+# Can't build vendor_boot-debug.img if we're not building a ramdisk.
+else ifndef BUILDING_RAMDISK_IMAGE
+  ifeq ($(PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE is true, but we're not building a ramdisk image. \
+      Skip building the debug vendor_boot image.)
+  endif
+# Can't build vendor_boot-debug.img if we're not building a vendor_boot.img.
+else ifndef BUILDING_VENDOR_BOOT_IMAGE
+  ifeq ($(PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE is true, but we're not building a vendor_boot image. \
+      Skip building the debug vendor_boot image.)
+  endif
+else
+  ifeq ($(PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE),)
+    BUILDING_DEBUG_VENDOR_BOOT_IMAGE := true
+  else ifeq ($(PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE),true)
+    BUILDING_DEBUG_VENDOR_BOOT_IMAGE := true
+  endif
+endif
+.KATI_READONLY := BUILDING_DEBUG_VENDOR_BOOT_IMAGE
+
+_has_boot_img_artifact :=
+ifneq ($(strip $(TARGET_NO_KERNEL)),true)
+  ifdef BUILDING_BOOT_IMAGE
+    _has_boot_img_artifact := true
+  endif
+  # BUILDING_RECOVERY_IMAGE && BOARD_USES_RECOVERY_AS_BOOT implies that
+  # recovery is being built with the file name *boot.img*, which still counts
+  # as "building boot.img".
+  ifdef BUILDING_RECOVERY_IMAGE
+    ifeq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
+      _has_boot_img_artifact := true
+    endif
+  endif
+endif
+
+# Are we building a debug boot image
+BUILDING_DEBUG_BOOT_IMAGE :=
+# Can't build boot-debug.img if BOARD_BUILD_SYSTEM_ROOT_IMAGE is true,
+# because building debug boot image requires a ramdisk.
+ifeq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
+  ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_BOOT_IMAGE is true, but so is BOARD_BUILD_SYSTEM_ROOT_IMAGE. \
+      Skip building the debug boot image.)
+  endif
+# Can't build boot-debug.img if we're not building a ramdisk.
+else ifndef BUILDING_RAMDISK_IMAGE
+  ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_BOOT_IMAGE is true, but we're not building a ramdisk image. \
+      Skip building the debug boot image.)
+  endif
+# Can't build boot-debug.img if we're not building a boot.img.
+else ifndef _has_boot_img_artifact
+  ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_BOOT_IMAGE is true, but we're not building a boot image. \
+      Skip building the debug boot image.)
+  endif
+else
+  ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),)
+    BUILDING_DEBUG_BOOT_IMAGE := true
+    # Don't build boot-debug.img if we're already building vendor_boot-debug.img.
+    ifdef BUILDING_DEBUG_VENDOR_BOOT_IMAGE
+      BUILDING_DEBUG_BOOT_IMAGE :=
+    endif
+  else ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),true)
+    BUILDING_DEBUG_BOOT_IMAGE := true
+  endif
+endif
+.KATI_READONLY := BUILDING_DEBUG_BOOT_IMAGE
+_has_boot_img_artifact :=
+
 # Are we building a userdata image
 BUILDING_USERDATA_IMAGE :=
 ifeq ($(PRODUCT_BUILD_USERDATA_IMAGE),)
diff --git a/core/product.mk b/core/product.mk
index 015fe44..8b45092 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -385,7 +385,9 @@
 _product_single_value_vars += PRODUCT_BUILD_USERDATA_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_RECOVERY_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_BOOT_IMAGE
+_product_single_value_vars += PRODUCT_BUILD_DEBUG_BOOT_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_VENDOR_BOOT_IMAGE
+_product_single_value_vars += PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_VBMETA_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_SUPER_EMPTY_IMAGE
 
@@ -427,6 +429,11 @@
 
 _product_single_value_vars += PRODUCT_INSTALL_EXTRA_FLATTENED_APEXES
 
+# Install a copy of the debug policy to the system_ext partition, and allow
+# init-second-stage to load debug policy from system_ext.
+# This option is only meant to be set by GSI products.
+_product_single_value_vars += PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT
+
 .KATI_READONLY := _product_single_value_vars _product_list_vars
 _product_var_list :=$= $(_product_single_value_vars) $(_product_list_vars)
 
diff --git a/core/product_config.mk b/core/product_config.mk
index 5c85fb8..679453e 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -350,6 +350,12 @@
   $(error Only one file may be in PRODUCT_ADB_KEYS: $(PRODUCT_ADB_KEYS))
 endif
 
+ifdef PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT
+  ifeq (,$(filter gsi_arm gsi_arm64 gsi_x86 gsi_x86_64,$(PRODUCT_NAME)))
+    $(error Only GSI products are allowed to set PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT)
+  endif
+endif
+
 ifndef PRODUCT_USE_DYNAMIC_PARTITIONS
   PRODUCT_USE_DYNAMIC_PARTITIONS := $(PRODUCT_RETROFIT_DYNAMIC_PARTITIONS)
 endif
diff --git a/target/product/gsi_release.mk b/target/product/gsi_release.mk
index 09417b5..a2a29ed 100644
--- a/target/product/gsi_release.mk
+++ b/target/product/gsi_release.mk
@@ -71,6 +71,8 @@
 
 # Do not build non-GSI partition images.
 PRODUCT_BUILD_CACHE_IMAGE := false
+PRODUCT_BUILD_DEBUG_BOOT_IMAGE := false
+PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE := false
 PRODUCT_BUILD_USERDATA_IMAGE := false
 PRODUCT_BUILD_VENDOR_IMAGE := false
 PRODUCT_BUILD_SUPER_PARTITION := false
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 0842af9..936ef88 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -136,6 +136,11 @@
 
   --android_jar_path <path>
       Path to the android.jar to repack the apex file.
+
+  --allow_gsi_debug_sepolicy
+      Allow the existence of the file 'userdebug_plat_sepolicy.cil' under
+      (/system/system_ext|/system_ext)/etc/selinux.
+      If not set, error out when the file exists.
 """
 
 from __future__ import print_function
@@ -189,6 +194,7 @@
 OPTIONS.gki_signing_algorithm = None
 OPTIONS.gki_signing_extra_args = None
 OPTIONS.android_jar_path = None
+OPTIONS.allow_gsi_debug_sepolicy = False
 
 
 AVB_FOOTER_ARGS_BY_PARTITION = {
@@ -658,7 +664,7 @@
     # Updates system_other.avbpubkey in /product/etc/.
     elif filename in (
         "PRODUCT/etc/security/avb/system_other.avbpubkey",
-            "SYSTEM/product/etc/security/avb/system_other.avbpubkey"):
+        "SYSTEM/product/etc/security/avb/system_other.avbpubkey"):
       # Only update system_other's public key, if the corresponding signing
       # key is specified via --avb_system_other_key.
       signing_key = OPTIONS.avb_keys.get("system_other")
@@ -671,9 +677,19 @@
     # Should NOT sign boot-debug.img.
     elif filename in (
         "BOOT/RAMDISK/force_debuggable",
-            "BOOT/RAMDISK/first_stage_ramdisk/force_debuggable"):
+        "BOOT/RAMDISK/first_stage_ramdisk/force_debuggable"):
       raise common.ExternalError("debuggable boot.img cannot be signed")
 
+    # Should NOT sign userdebug sepolicy file.
+    elif filename in (
+        "SYSTEM_EXT/etc/selinux/userdebug_plat_sepolicy.cil",
+        "SYSTEM/system_ext/etc/selinux/userdebug_plat_sepolicy.cil"):
+      if not OPTIONS.allow_gsi_debug_sepolicy:
+        raise common.ExternalError("debug sepolicy shouldn't be included")
+      else:
+        # Copy it verbatim if we allow the file to exist.
+        common.ZipWriteStr(output_tf_zip, out_info, data)
+
     # A non-APK file; copy it verbatim.
     else:
       common.ZipWriteStr(output_tf_zip, out_info, data)
@@ -1289,6 +1305,8 @@
       OPTIONS.gki_signing_algorithm = a
     elif o == "--gki_signing_extra_args":
       OPTIONS.gki_signing_extra_args = a
+    elif o == "--allow_gsi_debug_sepolicy":
+      OPTIONS.allow_gsi_debug_sepolicy = True
     else:
       return False
     return True
@@ -1339,6 +1357,7 @@
           "gki_signing_key=",
           "gki_signing_algorithm=",
           "gki_signing_extra_args=",
+          "allow_gsi_debug_sepolicy",
       ],
       extra_option_handler=option_handler)