diff --git a/apex/platform_bootclasspath_test.go b/apex/platform_bootclasspath_test.go
index 52b1689..ce12f46 100644
--- a/apex/platform_bootclasspath_test.go
+++ b/apex/platform_bootclasspath_test.go
@@ -20,6 +20,7 @@
 	"android/soong/android"
 	"android/soong/java"
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
 )
 
 // Contains tests for platform_bootclasspath logic from java/platform_bootclasspath.go that requires
@@ -174,6 +175,141 @@
 	})
 }
 
+// TestPlatformBootclasspath_AlwaysUsePrebuiltSdks verifies that the build does not fail when
+// AlwaysUsePrebuiltSdk() returns true. The structure of the modules in this test matches what
+// currently exists in some places in the Android build but it is not the intended structure. It is
+// in fact an invalid structure that should cause build failures. However, fixing that structure
+// will take too long so in the meantime this tests the workarounds to avoid build breakages.
+//
+// The main issues with this structure are:
+// 1. There is no prebuilt_bootclasspath_fragment referencing the "foo" java_sdk_library_import.
+// 2. There is no prebuilt_apex/apex_set which makes the dex implementation jar available to the
+//    prebuilt_bootclasspath_fragment and the "foo" java_sdk_library_import.
+//
+// Together these cause the following symptoms:
+// 1. The "foo" java_sdk_library_import does not have a dex implementation jar.
+// 2. The "foo" java_sdk_library_import does not have a myapex variant.
+//
+// TODO(b/179354495): Fix the structure in this test once the main Android build has been fixed.
+func TestPlatformBootclasspath_AlwaysUsePrebuiltSdks(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForTestWithPlatformBootclasspath,
+		prepareForTestWithMyapex,
+		// Configure two libraries, the first is a java_sdk_library whose prebuilt will be used because
+		// of AlwaysUsePrebuiltsSdk() but does not have an appropriate apex variant and does not provide
+		// a boot dex jar. The second is a normal library that is unaffected. The order matters because
+		// if the dependency on myapex:foo is filtered out because of either of those conditions then
+		// the dependencies resolved by the platform_bootclasspath will not match the configured list
+		// and so will fail the test.
+		java.FixtureConfigureUpdatableBootJars("myapex:foo", "myapex:bar"),
+		java.PrepareForTestWithJavaSdkLibraryFiles,
+		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+			variables.Always_use_prebuilt_sdks = proptools.BoolPtr(true)
+		}),
+		java.FixtureWithPrebuiltApis(map[string][]string{
+			"current": {},
+			"30":      {"foo"},
+		}),
+	).RunTestWithBp(t, `
+		apex {
+			name: "myapex",
+			key: "myapex.key",
+			bootclasspath_fragments: [
+				"mybootclasspath-fragment",
+			],
+			updatable: false,
+		}
+
+		apex_key {
+			name: "myapex.key",
+			public_key: "testkey.avbpubkey",
+			private_key: "testkey.pem",
+		}
+
+		java_library {
+			name: "bar",
+			srcs: ["b.java"],
+			installable: true,
+			apex_available: ["myapex"],
+			permitted_packages: ["bar"],
+		}
+
+		java_sdk_library {
+			name: "foo",
+			srcs: ["b.java"],
+			shared_library: false,
+			public: {
+				enabled: true,
+			},
+			apex_available: ["myapex"],
+			permitted_packages: ["foo"],
+		}
+
+		// A prebuilt java_sdk_library_import that is not preferred by default but will be preferred
+		// because AlwaysUsePrebuiltSdks() is true.
+		java_sdk_library_import {
+			name: "foo",
+			prefer: false,
+			shared_library: false,
+			public: {
+				jars: ["sdk_library/public/foo-stubs.jar"],
+				stub_srcs: ["sdk_library/public/foo_stub_sources"],
+				current_api: "sdk_library/public/foo.txt",
+				removed_api: "sdk_library/public/foo-removed.txt",
+				sdk_version: "current",
+			},
+			apex_available: ["myapex"],
+		}
+
+		// This always depends on the source foo module, its dependencies are not affected by the
+		// AlwaysUsePrebuiltSdks().
+		bootclasspath_fragment {
+			name: "mybootclasspath-fragment",
+			apex_available: [
+				"myapex",
+			],
+			contents: [
+				"foo", "bar",
+			],
+		}
+
+		platform_bootclasspath {
+			name: "myplatform-bootclasspath",
+		}
+`,
+	)
+
+	java.CheckPlatformBootclasspathModules(t, result, "myplatform-bootclasspath", []string{
+		// The configured contents of BootJars.
+		"platform:prebuilt_foo", // Note: This is the platform not myapex variant.
+		"myapex:bar",
+	})
+
+	// Make sure that the myplatform-bootclasspath has the correct dependencies.
+	CheckModuleDependencies(t, result.TestContext, "myplatform-bootclasspath", "android_common", []string{
+		// The following are stubs.
+		"platform:prebuilt_sdk_public_current_android",
+		"platform:prebuilt_sdk_system_current_android",
+		"platform:prebuilt_sdk_test_current_android",
+
+		// Not a prebuilt as no prebuilt existed when it was added.
+		"platform:legacy.core.platform.api.stubs",
+
+		// Needed for generating the boot image.
+		`platform:dex2oatd`,
+
+		// The platform_bootclasspath intentionally adds dependencies on both source and prebuilt
+		// modules when available as it does not know which one will be preferred.
+		//
+		// The source module has an APEX variant but the prebuilt does not.
+		"myapex:foo",
+		"platform:prebuilt_foo",
+
+		// Only a source module exists.
+		"myapex:bar",
+	})
+}
+
 // CheckModuleDependencies checks the dependencies of the selected module against the expected list.
 //
 // The expected list must be a list of strings of the form "<apex>:<module>", where <apex> is the
diff --git a/java/bootclasspath.go b/java/bootclasspath.go
index 02833ab..634959a 100644
--- a/java/bootclasspath.go
+++ b/java/bootclasspath.go
@@ -29,7 +29,7 @@
 
 func registerBootclasspathBuildComponents(ctx android.RegistrationContext) {
 	ctx.FinalDepsMutators(func(ctx android.RegisterMutatorsContext) {
-		ctx.BottomUp("bootclasspath_deps", bootclasspathDepsMutator)
+		ctx.BottomUp("bootclasspath_deps", bootclasspathDepsMutator).Parallel()
 	})
 }
 
@@ -95,6 +95,15 @@
 	if ctx.OtherModuleDependencyVariantExists(variations, prebuiltName) {
 		ctx.AddVariationDependencies(variations, tag, prebuiltName)
 		addedDep = true
+	} else if ctx.Config().AlwaysUsePrebuiltSdks() && len(variations) > 0 {
+		// TODO(b/179354495): Remove this code path once the Android build has been fully migrated to
+		//  use bootclasspath_fragment properly.
+		// Some prebuilt java_sdk_library modules do not yet have an APEX variations so try and add a
+		// dependency on the non-APEX variant.
+		if ctx.OtherModuleDependencyVariantExists(nil, prebuiltName) {
+			ctx.AddVariationDependencies(nil, tag, prebuiltName)
+			addedDep = true
+		}
 	}
 
 	// If no appropriate variant existing for this, so no dependency could be added, then it is an
diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index be202c0..c1068da 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -766,7 +766,7 @@
 			if len(pp) > 0 {
 				updatablePackages = append(updatablePackages, pp...)
 			} else {
-				ctx.ModuleErrorf("Missing permitted_packages")
+				ctx.OtherModuleErrorf(module, "Missing permitted_packages")
 			}
 		}
 	}
diff --git a/java/hiddenapi_modular.go b/java/hiddenapi_modular.go
index 2dceb65..f5afe5d 100644
--- a/java/hiddenapi_modular.go
+++ b/java/hiddenapi_modular.go
@@ -15,6 +15,7 @@
 package java
 
 import (
+	"fmt"
 	"strings"
 
 	"android/soong/android"
@@ -560,7 +561,25 @@
 	for _, module := range contents {
 		bootDexJar := module.bootDexJar()
 		if bootDexJar == nil {
-			ctx.ModuleErrorf("module %s does not provide a dex jar", module)
+			if ctx.Config().AlwaysUsePrebuiltSdks() {
+				// TODO(b/179354495): Remove this work around when it is unnecessary.
+				// Prebuilt modules like framework-wifi do not yet provide dex implementation jars. So,
+				// create a fake one that will cause a build error only if it is used.
+				fake := android.PathForModuleOut(ctx, "fake/boot-dex/%s.jar", module.Name())
+
+				// Create an error rule that pretends to create the output file but will actually fail if it
+				// is run.
+				ctx.Build(pctx, android.BuildParams{
+					Rule:   android.ErrorRule,
+					Output: fake,
+					Args: map[string]string{
+						"error": fmt.Sprintf("missing dependencies: boot dex jar for %s", module),
+					},
+				})
+				bootDexJars = append(bootDexJars, fake)
+			} else {
+				ctx.ModuleErrorf("module %s does not provide a dex jar", module)
+			}
 		} else {
 			bootDexJars = append(bootDexJars, bootDexJar)
 		}
diff --git a/java/platform_bootclasspath.go b/java/platform_bootclasspath.go
index c8fafed..6ebeb6b 100644
--- a/java/platform_bootclasspath.go
+++ b/java/platform_bootclasspath.go
@@ -242,8 +242,15 @@
 		} else {
 			name := ctx.OtherModuleName(m)
 			if apexInfo.IsForPlatform() {
-				// error: this jar is part of the platform
-				ctx.ModuleErrorf("module %q from platform is not allowed in the updatable boot jars list", name)
+				// If AlwaysUsePrebuiltSdks() returns true then it is possible that the updatable list will
+				// include platform variants of a prebuilt module due to workarounds elsewhere. In that case
+				// do not treat this as an error.
+				// TODO(b/179354495): Always treat this as an error when migration to bootclasspath_fragment
+				//  modules is complete.
+				if !ctx.Config().AlwaysUsePrebuiltSdks() {
+					// error: this jar is part of the platform
+					ctx.ModuleErrorf("module %q from platform is not allowed in the updatable boot jars list", name)
+				}
 			} else {
 				// TODO(b/177892522): Treat this as an error.
 				// Cannot do that at the moment because framework-wifi and framework-tethering are in the