diff --git a/CleanSpec.mk b/CleanSpec.mk
index bbeac6c..b9f6e13 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -395,6 +395,9 @@
 $(call add-clean-step, rm -rf $(TARGET_OUT_COMMON_INTERMEDIATES)/APPS/*_intermediates/src)
 $(call add-clean-step, rm -rf $(TARGET_OUT_COMMON_INTERMEDIATES)/JAVA_LIBRARIES/*_intermediates/src)
 
+$(call add-clean-step, rm -rf $(HOST_OUT_TESTCASES))
+$(call add-clean-step, rm -rf $(TARGET_OUT_TESTCASES))
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/base_rules.mk b/core/base_rules.mk
index 1da6554..1f55eae 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -537,6 +537,9 @@
 endif
 ALL_MODULES.$(my_register_name).REQUIRED := \
     $(strip $(ALL_MODULES.$(my_register_name).REQUIRED) $(my_required_modules))
+ALL_MODULES.$(my_register_name).EXPLICITLY_REQUIRED := \
+    $(strip $(ALL_MODULES.$(my_register_name).EXPLICITLY_REQUIRED)\
+        $(my_required_modules))
 ALL_MODULES.$(my_register_name).EVENT_LOG_TAGS := \
     $(ALL_MODULES.$(my_register_name).EVENT_LOG_TAGS) $(event_log_tags)
 ALL_MODULES.$(my_register_name).MAKEFILE := \
diff --git a/core/config_sanitizers.mk b/core/config_sanitizers.mk
index 5eaf7b1..57a7993 100644
--- a/core/config_sanitizers.mk
+++ b/core/config_sanitizers.mk
@@ -68,6 +68,12 @@
   my_sanitize_diag := $(filter-out cfi,$(my_sanitize_diag))
 endif
 
+# Disable CFI for arm32 (b/35157333).
+ifneq ($(filter arm,$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)),)
+  my_sanitize := $(filter-out cfi,$(my_sanitize))
+  my_sanitize_diag := $(filter-out cfi,$(my_sanitize_diag))
+endif
+
 # CFI needs gold linker, and mips toolchain does not have one.
 ifneq ($(filter mips mips64,$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)),)
   my_sanitize := $(filter-out cfi,$(my_sanitize))
diff --git a/core/dex_preopt_libart.mk b/core/dex_preopt_libart.mk
index 3cff9c8..41e5e87 100644
--- a/core/dex_preopt_libart.mk
+++ b/core/dex_preopt_libart.mk
@@ -124,5 +124,6 @@
 	--abort-on-hard-verifier-error \
 	--no-inline-from=core-oj.jar \
 	$(PRIVATE_DEX_PREOPT_FLAGS) \
+	$(PRIVATE_ART_FILE_PREOPT_FLAGS) \
 	$(GLOBAL_DEXPREOPT_FLAGS)
 endef
diff --git a/core/dex_preopt_odex_install.mk b/core/dex_preopt_odex_install.mk
index 52a67fe..9a15706 100644
--- a/core/dex_preopt_odex_install.mk
+++ b/core/dex_preopt_odex_install.mk
@@ -50,10 +50,14 @@
 
 built_odex :=
 built_vdex :=
+built_art :=
 installed_odex :=
 installed_vdex :=
+installed_art :=
 built_installed_odex :=
 built_installed_vdex :=
+built_installed_art :=
+
 ifdef LOCAL_DEX_PREOPT
 dexpreopt_boot_jar_module := $(filter $(DEXPREOPT_BOOT_JARS_MODULES),$(LOCAL_MODULE))
 ifdef dexpreopt_boot_jar_module
@@ -103,8 +107,10 @@
 
 built_odex := $(strip $(built_odex))
 built_vdex := $(strip $(built_vdex))
+built_art := $(strip $(built_art))
 installed_odex := $(strip $(installed_odex))
 installed_vdex := $(strip $(installed_vdex))
+installed_art := $(strip $(installed_art))
 
 ifdef built_odex
 ifndef LOCAL_DEX_PREOPT_FLAGS
@@ -113,16 +119,18 @@
 LOCAL_DEX_PREOPT_FLAGS := $(PRODUCT_DEX_PREOPT_DEFAULT_FLAGS)
 endif
 endif
-
 $(built_odex): PRIVATE_DEX_PREOPT_FLAGS := $(LOCAL_DEX_PREOPT_FLAGS)
 $(built_vdex): $(built_odex)
+$(built_art): $(built_odex)
 endif
 
 # Add the installed_odex to the list of installed files for this module.
 ALL_MODULES.$(my_register_name).INSTALLED += $(installed_odex)
 ALL_MODULES.$(my_register_name).INSTALLED += $(installed_vdex)
+ALL_MODULES.$(my_register_name).INSTALLED += $(installed_art)
 ALL_MODULES.$(my_register_name).BUILT_INSTALLED += $(built_installed_odex)
 ALL_MODULES.$(my_register_name).BUILT_INSTALLED += $(built_installed_vdex)
+ALL_MODULES.$(my_register_name).BUILT_INSTALLED += $(built_installed_art)
 
 # Record dex-preopt config.
 DEXPREOPT.$(LOCAL_MODULE).DEX_PREOPT := $(LOCAL_DEX_PREOPT)
@@ -138,6 +146,6 @@
 
 
 # Make sure to install the .odex and .vdex when you run "make <module_name>"
-$(my_all_targets): $(installed_odex) $(installed_vdex)
+$(my_all_targets): $(installed_odex) $(installed_vdex) $(installed_art)
 
 endif # LOCAL_DEX_PREOPT
diff --git a/core/main.mk b/core/main.mk
index cca0d21..dff0163 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1078,15 +1078,6 @@
 # Phony target to run all java compilations that use javac instead of jack.
 .PHONY: javac-check
 
-# To catch more build breakage, check build tests modules in eng and userdebug builds.
-ifneq ($(ANDROID_NO_TEST_CHECK),true)
-ifneq ($(TARGET_BUILD_PDK),true)
-ifneq ($(filter eng userdebug,$(TARGET_BUILD_VARIANT)),)
-droidcore : target-tests host-tests
-endif
-endif
-endif
-
 ifneq (,$(filter samplecode, $(MAKECMDGOALS)))
 .PHONY: samplecode
 sample_MODULES := $(sort $(call get-tagged-modules,samples))
diff --git a/core/product.mk b/core/product.mk
index 93d42fd..7d7c68b 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -289,7 +289,8 @@
 _product_stash_var_list += \
 	DEFAULT_SYSTEM_DEV_CERTIFICATE \
 	WITH_DEXPREOPT \
-	WITH_DEXPREOPT_BOOT_IMG_ONLY
+	WITH_DEXPREOPT_BOOT_IMG_ONLY \
+	WITH_DEXPREOPT_APP_IMAGE
 
 #
 # Mark the variables in _product_stash_var_list as readonly
diff --git a/core/setup_one_odex.mk b/core/setup_one_odex.mk
index 37aeb60..0afc5b7 100644
--- a/core/setup_one_odex.mk
+++ b/core/setup_one_odex.mk
@@ -36,6 +36,17 @@
 
 my_built_vdex := $(patsubst %.odex,%.vdex,$(my_built_odex))
 my_installed_vdex := $(patsubst %.odex,%.vdex,$(my_installed_odex))
+my_installed_art := $(patsubst %.odex,%.art,$(my_installed_odex))
+
+ifeq (true,$(WITH_DEXPREOPT_APP_IMAGE))
+my_built_art := $(patsubst %.odex,%.art,$(my_built_odex))
+$(my_built_odex): PRIVATE_ART_FILE_PREOPT_FLAGS := --app-image-file=$(my_built_art) \
+    --image-format=lz4
+$(eval $(call copy-one-file,$(my_built_art),$(my_installed_art)))
+built_art += $(my_built_art)
+installed_art += $(my_installed_art)
+built_installed_art += $(my_built_art):$(my_installed_art)
+endif
 
 $(eval $(call copy-one-file,$(my_built_odex),$(my_installed_odex)))
 $(eval $(call copy-one-file,$(my_built_vdex),$(my_installed_vdex)))
diff --git a/core/tasks/tools/package-modules.mk b/core/tasks/tools/package-modules.mk
index 24a7608..ef49d90 100644
--- a/core/tasks/tools/package-modules.mk
+++ b/core/tasks/tools/package-modules.mk
@@ -14,10 +14,20 @@
 my_copy_pairs :=
 my_pickup_files :=
 
+# Iterate over the modules and include their direct dependencies stated in the
+# LOCAL_REQUIRED_MODULES.
+my_modules_and_deps := $(my_modules)
+$(foreach m,$(my_modules),\
+  $(eval _explicitly_required := \
+    $(strip $(ALL_MODULES.$(m).EXPLICITLY_REQUIRED)\
+    $(ALL_MODULES.$(m)$(TARGET_2ND_ARCH_MODULE_SUFFIX).EXPLICITLY_REQUIRED)))\
+  $(eval my_modules_and_deps += $(_explicitly_required))\
+)
+
 # Iterate over modules' built files and installed files;
 # Calculate the dest files in the output zip file.
 
-$(foreach m,$(my_modules),\
+$(foreach m,$(my_modules_and_deps),\
   $(eval _pickup_files := $(strip $(ALL_MODULES.$(m).PICKUP_FILES)\
     $(ALL_MODULES.$(m)$(TARGET_2ND_ARCH_MODULE_SUFFIX).PICKUP_FILES)))\
   $(eval _built_files := $(strip $(ALL_MODULES.$(m).BUILT_INSTALLED)\
diff --git a/tools/fat16copy.py b/tools/fat16copy.py
index af8bd83..c20930a 100755
--- a/tools/fat16copy.py
+++ b/tools/fat16copy.py
@@ -234,11 +234,16 @@
     data.seek(0)
     data_file.write(data.read())
 
-  def new_subdirectory(self, name):
+  def open_subdirectory(self, name):
     """
-    Create a new subdirectory of this directory with the given name.
+    Open a subdirectory of this directory with the given name. If the
+    subdirectory doesn't exist, a new one is created instead.
     Returns a fat_dir().
     """
+    for dent in self.dentries:
+      if dent.longname == name:
+        return dent.open_directory()
+
     chunk = self.backing.fs.allocate(1)
     (shortname, ext) = self.make_short_name(name)
     new_dentry = self.add_dentry(ATTRIBUTE_SUBDIRECTORY, shortname,
@@ -751,7 +756,7 @@
     base = os.path.basename(item)
     if len(base) == 0:
       base = os.path.basename(item[:-1])
-    sub = directory.new_subdirectory(base)
+    sub = directory.open_subdirectory(base)
     for next_item in sorted(os.listdir(item)):
       add_item(sub, os.path.join(item, next_item))
   else:
diff --git a/tools/releasetools/blockimgdiff.py b/tools/releasetools/blockimgdiff.py
index 433a010..1edf5b2 100644
--- a/tools/releasetools/blockimgdiff.py
+++ b/tools/releasetools/blockimgdiff.py
@@ -635,7 +635,7 @@
     stash_map = {}
 
     # Create the map between a stash and its def/use points. For example, for a
-    # given stash of (raw_id, sr), stashes[raw_id] = (sr, def_cmd, use_cmd).
+    # given stash of (raw_id, sr), stash_map[raw_id] = (sr, def_cmd, use_cmd).
     for xf in self.transfers:
       # Command xf defines (stores) all the stashes in stash_before.
       for stash_raw_id, sr in xf.stash_before:
@@ -672,20 +672,10 @@
         # Check the post-command stashed_blocks.
         stashed_blocks_after = stashed_blocks
         if self.version == 2:
-          assert stash_raw_id not in stashes
-          if free_stash_ids:
-            sid = heapq.heappop(free_stash_ids)
-          else:
-            sid = next_stash_id
-            next_stash_id += 1
-          stashes[stash_raw_id] = sid
           stashed_blocks_after += sr.size()
         else:
           sh = self.HashBlocks(self.src, sr)
-          if sh in stashes:
-            stashes[sh] += 1
-          else:
-            stashes[sh] = 1
+          if sh not in stashes:
             stashed_blocks_after += sr.size()
 
         if stashed_blocks_after > max_allowed:
@@ -695,6 +685,20 @@
           replaced_cmds.append(use_cmd)
           print("%10d  %9s  %s" % (sr.size(), "explicit", use_cmd))
         else:
+          # Update the stashes map.
+          if self.version == 2:
+            assert stash_raw_id not in stashes
+            if free_stash_ids:
+              sid = heapq.heappop(free_stash_ids)
+            else:
+              sid = next_stash_id
+              next_stash_id += 1
+            stashes[stash_raw_id] = sid
+          else:
+            if sh in stashes:
+              stashes[sh] += 1
+            else:
+              stashes[sh] = 1
           stashed_blocks = stashed_blocks_after
 
       # "move" and "diff" may introduce implicit stashes in BBOTA v3. Prior to