diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index bf39404..2e4068d 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -166,6 +166,7 @@
 		"external/minijail":                      Bp2BuildDefaultTrueRecursively,
 		"external/objenesis":                     Bp2BuildDefaultTrueRecursively,
 		"external/openscreen":                    Bp2BuildDefaultTrueRecursively,
+		"external/ow2-asm":                       Bp2BuildDefaultTrueRecursively,
 		"external/pcre":                          Bp2BuildDefaultTrueRecursively,
 		"external/protobuf":                      Bp2BuildDefaultTrueRecursively,
 		"external/python/six":                    Bp2BuildDefaultTrueRecursively,
diff --git a/android/filegroup.go b/android/filegroup.go
index af4d89a..d21d146 100644
--- a/android/filegroup.go
+++ b/android/filegroup.go
@@ -122,16 +122,18 @@
 		if fg.ShouldConvertToProtoLibrary(ctx) {
 			// TODO(b/246997908): we can remove this tag if we could figure out a
 			// solution for this bug.
-			tags := []string{"manual"}
 			attrs := &ProtoAttrs{
 				Srcs:                srcs,
 				Strip_import_prefix: fg.properties.Path,
-				Tags:                tags,
 			}
 
+			tags := []string{"manual"}
 			ctx.CreateBazelTargetModule(
 				bazel.BazelTargetModuleProperties{Rule_class: "proto_library"},
-				CommonAttributes{Name: fg.Name() + convertedProtoLibrarySuffix},
+				CommonAttributes{
+					Name: fg.Name() + convertedProtoLibrarySuffix,
+					Tags: bazel.MakeStringListAttribute(tags),
+				},
 				attrs)
 		}
 
diff --git a/android/proto.go b/android/proto.go
index 3cac9a1..8204f77 100644
--- a/android/proto.go
+++ b/android/proto.go
@@ -164,7 +164,6 @@
 	Srcs                bazel.LabelListAttribute
 	Strip_import_prefix *string
 	Deps                bazel.LabelListAttribute
-	Tags                []string
 }
 
 // For each package in the include_dirs property a proto_library target should
diff --git a/dexpreopt/config.go b/dexpreopt/config.go
index eefda19..609a29c 100644
--- a/dexpreopt/config.go
+++ b/dexpreopt/config.go
@@ -96,6 +96,8 @@
 	// quickly silence build errors. This flag should be used with caution and only as a temporary
 	// measure, as it masks real errors and affects performance.
 	RelaxUsesLibraryCheck bool
+
+	EnableUffdGc bool // preopt with the assumption that userfaultfd GC will be used on device.
 }
 
 var allPlatformSystemServerJarsKey = android.NewOnceKey("allPlatformSystemServerJars")
diff --git a/dexpreopt/dexpreopt.go b/dexpreopt/dexpreopt.go
index fdfd22e..e3404a5 100644
--- a/dexpreopt/dexpreopt.go
+++ b/dexpreopt/dexpreopt.go
@@ -495,6 +495,10 @@
 		cmd.FlagWithInput("--profile-file=", profile)
 	}
 
+	if global.EnableUffdGc {
+		cmd.Flag("--runtime-arg").Flag("-Xgc:CMC")
+	}
+
 	rule.Install(odexPath, odexInstallPath)
 	rule.Install(vdexPath, vdexInstallPath)
 }
diff --git a/docs/perf.md b/docs/perf.md
index 694dcf1..5b53c8d 100644
--- a/docs/perf.md
+++ b/docs/perf.md
@@ -42,16 +42,29 @@
 ```
 
 If the elapsed time is much longer than the critical path then additional
-parallelism on the build machine will improve total build times.  If there are
+parallelism on the build machine will improve total build times. If there are
 long individual times listed in the critical path then improving build times
 for those steps or adjusting dependencies so that those steps can run earlier
 in the build graph will improve total build times.
 
 ### Soong
 
-Soong can be traced and profiled using the standard Go tools. It understands
-the `-cpuprofile`, `-trace`, and `-memprofile` command line arguments, but we
-don't currently have an easy way to enable them in the context of a full build.
+Soong proper (i.e., `soong_build` executable that processes the blueprint
+files) can be traced and profiled using the standard Go tools. It understands
+the `-trace`, `-cpuprofile`, and `-memprofile` command line arguments.
+Setting `SOONG_PROFILE_CPU` and/or `SOONG_PROFILE_MEM` environment variables
+for the build enables respective profiling, e.g., running
+
+```shell
+SOONG_PROFILE_CPU=/tmp/foo m ..._
+```
+
+saves CPU profile for each Soong invocation in /tmp/foo._step_ file, where
+_step_ is Soong execution step. The main step is `build`. The others as
+`bp2build_files`, `bp2build_workspace`, `modulegraph`, `queryview`,
+`api_bp2build`, `soong_docs` (not all of them necessarily run during the build).
+The profiles can be inspected with `go tool pprof` from the command line or
+with _Run>Open Profiler Snapshot_ in IntelliJ IDEA.
 
 ### Kati
 
diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index b3faae8..3effff6 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -752,6 +752,10 @@
 		cmd.FlagWithArg("--instruction-set-features=", global.InstructionSetFeatures[arch])
 	}
 
+	if global.EnableUffdGc {
+		cmd.Flag("--runtime-arg").Flag("-Xgc:CMC")
+	}
+
 	if global.BootFlags != "" {
 		cmd.Flag(global.BootFlags)
 	}
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 2173dae..8a291ad 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -304,6 +304,9 @@
 		flags = append(flags, "-I"+src.String())
 	}
 
+	minSdkVersion := j.MinSdkVersion(ctx).ApiLevel.FinalOrFutureInt()
+	flags = append(flags, fmt.Sprintf("--min_sdk_version=%v", minSdkVersion))
+
 	return strings.Join(flags, " "), deps
 }
 
diff --git a/java/java_test.go b/java/java_test.go
index 62c2845..ff15783 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -1370,6 +1370,39 @@
 	}
 }
 
+func TestAidlFlagsMinSdkVersionDroidstubs(t *testing.T) {
+	bpTemplate := `
+	droidstubs {
+		name: "foo-stubs",
+		srcs: ["foo.aidl"],
+		%s
+		system_modules: "none",
+	}
+	`
+	testCases := []struct {
+		desc                  string
+		sdkVersionBp          string
+		minSdkVersionExpected string
+	}{
+		{
+			desc:                  "sdk_version not set, module compiles against private platform APIs",
+			sdkVersionBp:          ``,
+			minSdkVersionExpected: "10000",
+		},
+		{
+			desc:                  "sdk_version set to none, module does not build against an SDK",
+			sdkVersionBp:          `sdk_version: "none",`,
+			minSdkVersionExpected: "10000",
+		},
+	}
+	for _, tc := range testCases {
+		ctx := prepareForJavaTest.RunTestWithBp(t, fmt.Sprintf(bpTemplate, tc.sdkVersionBp))
+		aidlCmd := ctx.ModuleForTests("foo-stubs", "android_common").Rule("aidl").RuleParams.Command
+		expected := "--min_sdk_version=" + tc.minSdkVersionExpected
+		android.AssertStringDoesContain(t, "aidl command conatins incorrect min_sdk_version for testCse: "+tc.desc, aidlCmd, expected)
+	}
+}
+
 func TestAidlEnforcePermissions(t *testing.T) {
 	ctx, _ := testJava(t, `
 		java_library {
diff --git a/java/legacy_core_platform_api_usage.go b/java/legacy_core_platform_api_usage.go
index 1f374b4..6cb549e 100644
--- a/java/legacy_core_platform_api_usage.go
+++ b/java/legacy_core_platform_api_usage.go
@@ -53,15 +53,6 @@
 	"SettingsGoogleOverlayCoral",
 	"SettingsGoogleOverlayFlame",
 	"SettingsLib",
-	"SettingsOverlayG020I",
-	"SettingsOverlayG020I_VN",
-	"SettingsOverlayG020J",
-	"SettingsOverlayG020M",
-	"SettingsOverlayG020N",
-	"SettingsOverlayG020P",
-	"SettingsOverlayG020Q",
-	"SettingsOverlayG025H",
-	"SettingsOverlayG5NZ6",
 	"SettingsRoboTests",
 	"SimContact",
 	"SimContacts",
diff --git a/java/sdk_library.go b/java/sdk_library.go
index fad1df7..56e5550 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -1648,6 +1648,7 @@
 	// shared libs and static libs. So we need to add both of these libs to Libs property.
 	props.Libs = module.properties.Libs
 	props.Libs = append(props.Libs, module.properties.Static_libs...)
+	props.Libs = append(props.Libs, module.sdkLibraryProperties.Stub_only_libs...)
 	props.Aidl.Include_dirs = module.deviceProperties.Aidl.Include_dirs
 	props.Aidl.Local_include_dirs = module.deviceProperties.Aidl.Local_include_dirs
 	props.Java_version = module.properties.Java_version
diff --git a/java/sdk_library_test.go b/java/sdk_library_test.go
index 096bca8..210bfc3 100644
--- a/java/sdk_library_test.go
+++ b/java/sdk_library_test.go
@@ -1385,3 +1385,29 @@
 			}
 		`)
 }
+
+func TestJavaSdkLibrary_StubOnlyLibs_PassedToDroidstubs(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForJavaTest,
+		PrepareForTestWithJavaSdkLibraryFiles,
+		FixtureWithLastReleaseApis("foo"),
+	).RunTestWithBp(t, `
+		java_sdk_library {
+			name: "foo",
+			srcs: ["a.java"],
+			public: {
+				enabled: true,
+			},
+			stub_only_libs: ["bar-lib"],
+		}
+
+		java_library {
+			name: "bar-lib",
+			srcs: ["b.java"],
+		}
+		`)
+
+	// The foo.stubs.source should depend on bar-lib
+	fooStubsSources := result.ModuleForTests("foo.stubs.source", "android_common").Module().(*Droidstubs)
+	android.AssertStringListContains(t, "foo stubs should depend on bar-lib", fooStubsSources.Javadoc.properties.Libs, "bar-lib")
+}
diff --git a/sdk/sdk_test.go b/sdk/sdk_test.go
index 2f9aee9..108a664 100644
--- a/sdk/sdk_test.go
+++ b/sdk/sdk_test.go
@@ -409,60 +409,6 @@
 		)
 	})
 
-	t.Run("SOONG_SDK_SNAPSHOT_PREFER=true", func(t *testing.T) {
-		result := android.GroupFixturePreparers(
-			preparer,
-			android.FixtureMergeEnv(map[string]string{
-				"SOONG_SDK_SNAPSHOT_PREFER": "true",
-			}),
-		).RunTest(t)
-
-		checkZipFile(t, result, "out/soong/.intermediates/mysdk/common_os/mysdk-current.zip")
-
-		CheckSnapshot(t, result, "mysdk", "",
-			checkAndroidBpContents(`
-// This is auto-generated. DO NOT EDIT.
-
-java_import {
-    name: "myjavalib",
-    prefer: true,
-    visibility: ["//visibility:public"],
-    apex_available: ["//apex_available:platform"],
-    jars: ["java/myjavalib.jar"],
-}
-			`),
-		)
-	})
-
-	t.Run("SOONG_SDK_SNAPSHOT_USE_SOURCE_CONFIG_VAR=module:build_from_source", func(t *testing.T) {
-		result := android.GroupFixturePreparers(
-			preparer,
-			android.FixtureMergeEnv(map[string]string{
-				"SOONG_SDK_SNAPSHOT_USE_SOURCE_CONFIG_VAR": "module:build_from_source",
-			}),
-		).RunTest(t)
-
-		checkZipFile(t, result, "out/soong/.intermediates/mysdk/common_os/mysdk-current.zip")
-
-		CheckSnapshot(t, result, "mysdk", "",
-			checkAndroidBpContents(`
-// This is auto-generated. DO NOT EDIT.
-
-java_import {
-    name: "myjavalib",
-    prefer: false,
-    use_source_config_var: {
-        config_namespace: "module",
-        var_name: "build_from_source",
-    },
-    visibility: ["//visibility:public"],
-    apex_available: ["//apex_available:platform"],
-    jars: ["java/myjavalib.jar"],
-}
-			`),
-		)
-	})
-
 	t.Run("SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE=S", func(t *testing.T) {
 		result := android.GroupFixturePreparers(
 			prepareForSdkTestWithJava,
diff --git a/sdk/update.go b/sdk/update.go
index 92a13fa..baa2033 100644
--- a/sdk/update.go
+++ b/sdk/update.go
@@ -34,41 +34,6 @@
 // Environment variables that affect the generated snapshot
 // ========================================================
 //
-// SOONG_SDK_SNAPSHOT_PREFER
-//     By default every module in the generated snapshot has prefer: false. Building it
-//     with SOONG_SDK_SNAPSHOT_PREFER=true will force them to use prefer: true.
-//
-// SOONG_SDK_SNAPSHOT_USE_SOURCE_CONFIG_VAR
-//     If set this specifies the Soong config var that can be used to control whether the prebuilt
-//     modules from the generated snapshot or the original source modules. Values must be a colon
-//     separated pair of strings, the first of which is the Soong config namespace, and the second
-//     is the name of the variable within that namespace.
-//
-//     The config namespace and var name are used to set the `use_source_config_var` property. That
-//     in turn will cause the generated prebuilts to use the soong config variable to select whether
-//     source or the prebuilt is used.
-//     e.g. If an sdk snapshot is built using:
-//       m SOONG_SDK_SNAPSHOT_USE_SOURCE_CONFIG_VAR=acme:build_from_source sdkextensions-sdk
-//     Then the resulting snapshot will include:
-//       use_source_config_var: {
-//         config_namespace: "acme",
-//         var_name: "build_from_source",
-//       }
-//
-//     Assuming that the config variable is defined in .mk using something like:
-//       $(call add_soong_config_namespace,acme)
-//       $(call add_soong_config_var_value,acme,build_from_source,true)
-//
-//     Then when the snapshot is unpacked in the repository it will have the following behavior:
-//       m droid - will use the sdkextensions-sdk prebuilts if present. Otherwise, it will use the
-//           sources.
-//       m SOONG_CONFIG_acme_build_from_source=true droid - will use the sdkextensions-sdk
-//            sources, if present. Otherwise, it will use the prebuilts.
-//
-//     This is a temporary mechanism to control the prefer flags and will be removed once a more
-//     maintainable solution has been implemented.
-//     TODO(b/174997203): Remove when no longer necessary.
-//
 // SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE
 //     This allows the target build release (i.e. the release version of the build within which
 //     the snapshot will be used) of the snapshot to be specified. If unspecified then it defaults
@@ -2019,29 +1984,12 @@
 
 	// Do not add the prefer property if the member snapshot module is a source module type.
 	moduleCtx := ctx.sdkMemberContext
-	config := moduleCtx.Config()
 	if !memberType.UsesSourceModuleTypeInSnapshot() {
-		// Set the prefer based on the environment variable. This is a temporary work around to allow a
-		// snapshot to be created that sets prefer: true.
-		// TODO(b/174997203): Remove once the ability to select the modules to prefer can be done
-		//  dynamically at build time not at snapshot generation time.
-		prefer := config.IsEnvTrue("SOONG_SDK_SNAPSHOT_PREFER")
-
 		// Set prefer. Setting this to false is not strictly required as that is the default but it does
 		// provide a convenient hook to post-process the generated Android.bp file, e.g. in tests to
 		// check the behavior when a prebuilt is preferred. It also makes it explicit what the default
 		// behavior is for the module.
-		bpModule.insertAfter("name", "prefer", prefer)
-
-		configVar := config.Getenv("SOONG_SDK_SNAPSHOT_USE_SOURCE_CONFIG_VAR")
-		if configVar != "" {
-			parts := strings.Split(configVar, ":")
-			cfp := android.ConfigVarProperties{
-				Config_namespace: proptools.StringPtr(parts[0]),
-				Var_name:         proptools.StringPtr(parts[1]),
-			}
-			bpModule.insertAfter("prefer", "use_source_config_var", cfp)
-		}
+		bpModule.insertAfter("name", "prefer", false)
 	}
 
 	variants := selectApexVariantsWhereAvailable(ctx, member.variants)
diff --git a/ui/build/dumpvars.go b/ui/build/dumpvars.go
index adc56ac..b3b3866 100644
--- a/ui/build/dumpvars.go
+++ b/ui/build/dumpvars.go
@@ -154,10 +154,7 @@
 	"HOST_CROSS_OS",
 	"BUILD_ID",
 	"OUT_DIR",
-	"SOONG_SDK_SNAPSHOT_PREFER",
 	"SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE",
-	"SOONG_SDK_SNAPSHOT_USE_SOURCE_CONFIG_VAR",
-	"SOONG_SDK_SNAPSHOT_VERSION",
 }
 
 func Banner(make_vars map[string]string) string {
diff --git a/ui/build/soong.go b/ui/build/soong.go
index c0bee4e..abaf5ae 100644
--- a/ui/build/soong.go
+++ b/ui/build/soong.go
@@ -195,6 +195,12 @@
 
 	allArgs = append(allArgs, commonArgs...)
 	allArgs = append(allArgs, environmentArgs(config, name)...)
+	if profileCpu := os.Getenv("SOONG_PROFILE_CPU"); profileCpu != "" {
+		allArgs = append(allArgs, "--cpuprofile", profileCpu+"."+name)
+	}
+	if profileMem := os.Getenv("SOONG_PROFILE_MEM"); profileMem != "" {
+		allArgs = append(allArgs, "--memprofile", profileMem+"."+name)
+	}
 	allArgs = append(allArgs, "Android.bp")
 
 	return bootstrap.PrimaryBuilderInvocation{