diff --git a/core/Makefile b/core/Makefile
index 1acf2ff..002e955 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -12,9 +12,11 @@
 # The filter part means "only eval the copy-one-file rule if this
 # src:dest pair is the first one to match the same dest"
 #$(1): the src:dest pair
+#$(2): the dest
 define check-product-copy-files
-$(if $(filter %.apk, $(call word-colon, 2, $(1))),$(error \
-    Prebuilt apk found in PRODUCT_COPY_FILES: $(1), use BUILD_PREBUILT instead!))
+$(if $(filter-out $(TARGET_COPY_OUT_SYSTEM_OTHER)/%,$(2)), \
+  $(if $(filter %.apk, $(2)),$(error \
+     Prebuilt apk found in PRODUCT_COPY_FILES: $(1), use BUILD_PREBUILT instead!)))
 endef
 # filter out the duplicate <source file>:<dest file> pairs.
 unique_product_copy_files_pairs :=
@@ -26,7 +28,7 @@
 $(foreach cf,$(unique_product_copy_files_pairs), \
     $(eval _src := $(call word-colon,1,$(cf))) \
     $(eval _dest := $(call word-colon,2,$(cf))) \
-    $(call check-product-copy-files,$(cf)) \
+    $(call check-product-copy-files,$(cf),$(_dest)) \
     $(if $(filter $(unique_product_copy_files_destinations),$(_dest)), \
         $(eval product_copy_files_ignored += $(cf)), \
         $(eval _fulldest := $(call append-path,$(PRODUCT_OUT),$(_dest))) \
@@ -2453,14 +2455,14 @@
   external/avb/test/data/atx_metadata.bin \
   external/avb/test/data/testkey_atx_psk.pem \
   external/avb/test/data/testkey_rsa4096.pem \
-  $(sort $(shell find system/update_engine/scripts -name \*.pyc -prune -o -type f -print)) \
-  $(sort $(shell find build/target/product/security -type f -name \*.x509.pem -o -name \*.pk8 -o \
+  $(sort $(shell find system/update_engine/scripts -name "*.pyc" -prune -o -type f -print)) \
+  $(sort $(shell find build/target/product/security -type f -name "*.x509.pem" -o -name "*.pk8" -o \
       -name verity_key)) \
-  $(sort $(shell find device $(wildcard vendor) -type f -name \*.pk8 -o -name verifiedboot\* -o \
-      -name \*.x509.pem -o -name oem\*.prop))
+  $(sort $(shell find device $(wildcard vendor) -type f -name "*.pk8" -o -name "verifiedboot*" -o \
+      -name "*.x509.pem" -o -name "oem*.prop"))
 
 OTATOOLS_RELEASETOOLS := \
-  $(sort $(shell find build/make/tools/releasetools -name \*.pyc -prune -o -type f))
+  $(sort $(shell find build/make/tools/releasetools -name "*.pyc" -prune -o -type f))
 
 ifeq (true,$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VBOOT))
 OTATOOLS_DEPS += \
diff --git a/core/aapt2.mk b/core/aapt2.mk
index 109bb39..4385b4d 100644
--- a/core/aapt2.mk
+++ b/core/aapt2.mk
@@ -66,6 +66,8 @@
 
 my_static_library_resources := $(foreach l, $(call reverse-list,$(LOCAL_STATIC_ANDROID_LIBRARIES)),\
   $(call intermediates-dir-for,JAVA_LIBRARIES,$(l),,COMMON)/package-res.apk)
+my_static_library_extra_packages := $(foreach l, $(call reverse-list,$(LOCAL_STATIC_ANDROID_LIBRARIES)),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(l),,COMMON)/extra_packages)
 my_shared_library_resources := $(foreach l, $(LOCAL_SHARED_ANDROID_LIBRARIES),\
   $(call intermediates-dir-for,JAVA_LIBRARIES,$(l),,COMMON)/package-res.apk)
 
@@ -81,6 +83,8 @@
 my_srcjar := $(intermediates.COMMON)/aapt2.srcjar
 LOCAL_SRCJARS += $(my_srcjar)
 
+aapt_extra_packages := $(intermediates.COMMON)/extra_packages
+
 $(my_res_package): PRIVATE_RES_FLAT := $(my_res_resources_flat)
 $(my_res_package): PRIVATE_OVERLAY_FLAT := $(my_static_library_resources) $(my_resources_flata) $(my_overlay_resources_flat)
 $(my_res_package): PRIVATE_SHARED_ANDROID_LIBRARIES := $(my_shared_library_resources)
@@ -88,7 +92,9 @@
 $(my_res_package): PRIVATE_ASSET_DIRS := $(my_asset_dirs)
 $(my_res_package): PRIVATE_JAVA_GEN_DIR := $(intermediates.COMMON)/aapt2
 $(my_res_package): PRIVATE_SRCJAR := $(my_srcjar)
-$(my_res_package): .KATI_IMPLICIT_OUTPUTS := $(my_srcjar)
+$(my_res_package): PRIVATE_STATIC_LIBRARY_EXTRA_PACKAGES := $(my_static_library_extra_packages)
+$(my_res_package): PRIVATE_AAPT_EXTRA_PACKAGES := $(aapt_extra_packages)
+$(my_res_package): .KATI_IMPLICIT_OUTPUTS := $(my_srcjar) $(aapt_extra_packages)
 
 ifdef R_file_stamp
 $(my_res_package): PRIVATE_R_FILE_STAMP := $(R_file_stamp)
@@ -112,8 +118,8 @@
 $(my_res_package): $(full_android_manifest) $(my_static_library_resources) $(my_shared_library_resources)
 $(my_res_package): $(my_full_asset_paths)
 $(my_res_package): $(my_res_resources_flat) $(my_overlay_resources_flat) \
-  $(my_resources_flata) $(my_static_library_resources) \
-  $(AAPT2) $(SOONG_ZIP)
+  $(my_resources_flata) $(my_static_library_resources) $(my_static_library_extra_packages) \
+  $(AAPT2) $(SOONG_ZIP) $(EXTRACT_JAR_PACKAGES)
 	@echo "AAPT2 link $@"
 	$(call aapt2-link)
 ifdef R_file_stamp
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index eac5987..3325752 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -244,6 +244,7 @@
 LOCAL_SOONG_PROGUARD_DICT :=
 LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE :=
 LOCAL_SOONG_RRO_DIRS :=
+LOCAL_SOONG_STATIC_LIBRARY_EXTRA_PACKAGES :=
 LOCAL_DROIDDOC_STUBS_SRCJAR :=
 LOCAL_DROIDDOC_DOC_ZIP :=
 # '',true
diff --git a/core/config.mk b/core/config.mk
index 9e61290..3664c6c 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -99,6 +99,11 @@
 # Some specific paths to tools
 SRC_DROIDDOC_DIR := $(TOPDIR)build/make/tools/droiddoc
 
+# Mark some inputs as readonly
+ifdef TARGET_DEVICE_DIR
+  .KATI_READONLY := TARGET_DEVICE_DIR
+endif
+
 # Set up efficient math functions which are used in make.
 # Here since this file is included by envsetup as well as during build.
 include $(BUILD_SYSTEM)/math.mk
diff --git a/core/definitions.mk b/core/definitions.mk
index 6f029e9..092a778 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2125,6 +2125,7 @@
 $(call dump-words-to-file,$(PRIVATE_OVERLAY_FLAT),$(dir $@)aapt2-flat-overlay-list)
 $(hide) $(AAPT2) link -o $@ \
   $(PRIVATE_AAPT_FLAGS) \
+  $(if $(PRIVATE_STATIC_LIBRARY_EXTRA_PACKAGES),$$(cat $(PRIVATE_STATIC_LIBRARY_EXTRA_PACKAGES))) \
   $(addprefix --manifest ,$(PRIVATE_ANDROID_MANIFEST)) \
   $(addprefix -I ,$(PRIVATE_AAPT_INCLUDES)) \
   $(addprefix -I ,$(PRIVATE_SHARED_ANDROID_LIBRARIES)) \
@@ -2143,6 +2144,7 @@
   -R \@$(dir $@)aapt2-flat-overlay-list \
   \@$(dir $@)aapt2-flat-list
 $(SOONG_ZIP) -o $(PRIVATE_SRCJAR) -C $(PRIVATE_JAVA_GEN_DIR) -D $(PRIVATE_JAVA_GEN_DIR)
+$(EXTRACT_JAR_PACKAGES) -i $(PRIVATE_SRCJAR) -o $(PRIVATE_AAPT_EXTRA_PACKAGES) --prefix '--extra-packages '
 endef
 
 ###########################################################
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 12b5869..1a36703 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -241,17 +241,26 @@
 # or under vendor/*/$(TARGET_DEVICE).  Search in both places, but
 # make sure only one exists.
 # Real boards should always be associated with an OEM vendor.
-board_config_mk := \
-	$(strip $(sort $(wildcard \
-		$(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)/BoardConfig.mk \
-		$(shell test -d device && find -L device -maxdepth 4 -path '*/$(TARGET_DEVICE)/BoardConfig.mk') \
-		$(shell test -d vendor && find -L vendor -maxdepth 4 -path '*/$(TARGET_DEVICE)/BoardConfig.mk') \
-	)))
-ifeq ($(board_config_mk),)
-  $(error No config file found for TARGET_DEVICE $(TARGET_DEVICE))
-endif
-ifneq ($(words $(board_config_mk)),1)
-  $(error Multiple board config files for TARGET_DEVICE $(TARGET_DEVICE): $(board_config_mk))
+ifdef TARGET_DEVICE_DIR
+  ifneq ($(origin TARGET_DEVICE_DIR),command line)
+    $(error TARGET_DEVICE_DIR may not be set manually)
+  endif
+  board_config_mk := $(TARGET_DEVICE_DIR)/BoardConfig.mk
+else
+  board_config_mk := \
+    $(strip $(sort $(wildcard \
+      $(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)/BoardConfig.mk \
+      $(shell test -d device && find -L device -maxdepth 4 -path '*/$(TARGET_DEVICE)/BoardConfig.mk') \
+      $(shell test -d vendor && find -L vendor -maxdepth 4 -path '*/$(TARGET_DEVICE)/BoardConfig.mk') \
+    )))
+  ifeq ($(board_config_mk),)
+    $(error No config file found for TARGET_DEVICE $(TARGET_DEVICE))
+  endif
+  ifneq ($(words $(board_config_mk)),1)
+    $(error Multiple board config files for TARGET_DEVICE $(TARGET_DEVICE): $(board_config_mk))
+  endif
+  TARGET_DEVICE_DIR := $(patsubst %/,%,$(dir $(board_config_mk)))
+  .KATI_READONLY := TARGET_DEVICE_DIR
 endif
 include $(board_config_mk)
 ifeq ($(TARGET_ARCH),)
@@ -261,7 +270,6 @@
   $(warning *** Unsupported option MALLOC_IMPL defined by board config: $(board_config_mk).)
   $(error Use `MALLOC_SVELTE := true` to configure jemalloc for low-memory)
 endif
-TARGET_DEVICE_DIR := $(patsubst %/,%,$(dir $(board_config_mk)))
 board_config_mk :=
 
 ###########################################
diff --git a/core/java_common.mk b/core/java_common.mk
index 9fd6bfe..2695aff 100644
--- a/core/java_common.mk
+++ b/core/java_common.mk
@@ -225,6 +225,15 @@
 
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_RMTYPEDEFS := $(LOCAL_RMTYPEDEFS)
 
+# Sanity check class path vars.
+disallowed_deps := $(foreach sdk,$(TARGET_AVAILABLE_SDK_VERSIONS),$(call resolve-prebuilt-sdk-module,$(sdk)))
+disallowed_deps += $(foreach sdk,$(TARGET_AVAILABLE_SDK_VERSIONS),\
+  $(foreach sdk_lib,$(JAVA_SDK_LIBRARIES),$(call resolve-prebuilt-sdk-module,$(sdk),$(sdk_lib))))
+bad_deps := $(filter $(disallowed_deps),$(LOCAL_JAVA_LIBRARIES) $(LOCAL_STATIC_JAVA_LIBRARIES))
+ifneq (,$(bad_deps))
+  $(call pretty-error,SDK modules should not be depended on directly. Please use LOCAL_SDK_VERSION for $(bad_deps))
+endif
+
 full_java_bootclasspath_libs :=
 empty_bootclasspath :=
 my_system_modules :=
diff --git a/core/product.mk b/core/product.mk
index 1a15c9f..976c939 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -23,21 +23,12 @@
 # and the .mk suffix) of the product makefile, "<product_name>:" can be
 # omitted.
 
-# Search for AndroidProducts.mks in the given dir.
-# $(1): the path to the dir
-define _search-android-products-files-in-dir
-$(sort $(shell test -d $(1) && find -L $(1) \
-  -maxdepth 6 \
-  -name .git -prune \
-  -o -name AndroidProducts.mk -print))
-endef
-
 #
 # Returns the list of all AndroidProducts.mk files.
 # $(call ) isn't necessary.
 #
 define _find-android-products-files
-$(foreach d, device vendor product,$(call _search-android-products-files-in-dir,$(d))) \
+$(file <$(OUT_DIR)/.module_paths/AndroidProducts.mk.list) \
   $(SRC_TARGET_DIR)/product/AndroidProducts.mk
 endef
 
diff --git a/core/soong_java_prebuilt.mk b/core/soong_java_prebuilt.mk
index 3773c07..58735cd 100644
--- a/core/soong_java_prebuilt.mk
+++ b/core/soong_java_prebuilt.mk
@@ -61,6 +61,9 @@
 
   $(call add-dependency,$(LOCAL_BUILT_MODULE),$(my_proguard_flags))
 
+  my_static_library_extra_packages := $(intermediates.COMMON)/extra_packages
+  $(eval $(call copy-one-file,$(LOCAL_SOONG_STATIC_LIBRARY_EXTRA_PACKAGES),$(my_static_library_extra_packages)))
+  $(call add-dependency,$(LOCAL_BUILT_MODULE),$(my_static_library_extra_packages))
 endif # LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE
 
 ifneq ($(TURBINE_ENABLED),false)
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 773dc24..8c36359 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -39,9 +39,9 @@
   include $(INTERNAL_BUILD_ID_MAKEFILE)
 endif
 
-DEFAULT_PLATFORM_VERSION := PPR1
-MIN_PLATFORM_VERSION := PPR1
-MAX_PLATFORM_VERSION := PPR1
+DEFAULT_PLATFORM_VERSION := QPR1
+MIN_PLATFORM_VERSION := QPR1
+MAX_PLATFORM_VERSION := QPR1
 
 ALLOWED_VERSIONS := $(call allowed-platform-versions,\
   $(MIN_PLATFORM_VERSION),\
@@ -83,10 +83,12 @@
 # in the following text file:
 # cts/tests/tests/os/assets/platform_versions.txt
 PLATFORM_VERSION.PPR1 := P
+PLATFORM_VERSION.QPR1 := Q
 
 # These are the current development codenames, if the build is not a final
 # release build.  If this is a final release build, it is simply "REL".
 PLATFORM_VERSION_CODENAME.PPR1 := P
+PLATFORM_VERSION_CODENAME.QPR1 := Q
 
 ifndef PLATFORM_VERSION
   PLATFORM_VERSION := $(PLATFORM_VERSION.$(TARGET_PLATFORM_VERSION))