diff --git a/apex/apex_test.go b/apex/apex_test.go
index afc395d..68182a7 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -4542,7 +4542,12 @@
 }
 
 func TestBootDexJarsFromSourcesAndPrebuilts(t *testing.T) {
-	preparer := java.FixtureConfigureBootJars("myapex:libfoo", "myapex:libbar")
+	preparer := android.GroupFixturePreparers(
+		java.FixtureConfigureBootJars("myapex:libfoo", "myapex:libbar"),
+		// Make sure that the frameworks/base/Android.bp file exists as otherwise hidden API encoding
+		// is disabled.
+		android.FixtureAddTextFile("frameworks/base/Android.bp", ""),
+	)
 
 	checkBootDexJarPath := func(t *testing.T, ctx *android.TestContext, stem string, bootDexJarPath string) {
 		t.Helper()
diff --git a/java/hiddenapi.go b/java/hiddenapi.go
index 2c0655f..829c473 100644
--- a/java/hiddenapi.go
+++ b/java/hiddenapi.go
@@ -92,6 +92,12 @@
 
 	h.configurationName = configurationName
 
+	// If the frameworks/base directories does not exist and no prebuilt hidden API flag files have
+	// been configured then it is not possible to do hidden API encoding.
+	if !ctx.Config().FrameworksBaseDirExists(ctx) && ctx.Config().PrebuiltHiddenApiDir(ctx) == "" {
+		return
+	}
+
 	// It is important that hiddenapi information is only gathered for/from modules that are actually
 	// on the boot jars list because the runtime only enforces access to the hidden API for the
 	// bootclassloader. If information is gathered for modules not on the list then that will cause
@@ -303,11 +309,7 @@
 	}
 
 	enforceHiddenApiFlagsToAllMembers := true
-	// If frameworks/base doesn't exist we must be building with the 'master-art' manifest.
-	// Disable assertion that all methods/fields have hidden API flags assigned.
-	if !ctx.Config().FrameworksBaseDirExists(ctx) {
-		enforceHiddenApiFlagsToAllMembers = false
-	}
+
 	// b/149353192: when a module is instrumented, jacoco adds synthetic members
 	// $jacocoData and $jacocoInit. Since they don't exist when building the hidden API flags,
 	// don't complain when we don't find hidden API flags for the synthetic members.
diff --git a/java/hiddenapi_singleton.go b/java/hiddenapi_singleton.go
index 676a0e7..848aa59 100644
--- a/java/hiddenapi_singleton.go
+++ b/java/hiddenapi_singleton.go
@@ -117,7 +117,6 @@
 }
 
 type hiddenAPISingleton struct {
-	flags android.Path
 }
 
 // hiddenAPI singleton rules
@@ -136,17 +135,10 @@
 	// consistency.
 
 	if ctx.Config().PrebuiltHiddenApiDir(ctx) != "" {
-		h.flags = prebuiltFlagsRule(ctx)
+		prebuiltFlagsRule(ctx)
 		prebuiltIndexRule(ctx)
 		return
 	}
-
-	// These rules depend on files located in frameworks/base, skip them if running in a tree that doesn't have them.
-	if ctx.Config().FrameworksBaseDirExists(ctx) {
-		h.flags = flagsRule(ctx)
-	} else {
-		h.flags = emptyFlagsRule(ctx)
-	}
 }
 
 // Checks to see whether the supplied module variant is in the list of boot jars.
@@ -187,7 +179,7 @@
 	return true
 }
 
-func prebuiltFlagsRule(ctx android.SingletonContext) android.Path {
+func prebuiltFlagsRule(ctx android.SingletonContext) {
 	outputPath := hiddenAPISingletonPaths(ctx).flags
 	inputPath := android.PathForSource(ctx, ctx.Config().PrebuiltHiddenApiDir(ctx), "hiddenapi-flags.csv")
 
@@ -196,8 +188,6 @@
 		Output: outputPath,
 		Input:  inputPath,
 	})
-
-	return outputPath
 }
 
 func prebuiltIndexRule(ctx android.SingletonContext) {
@@ -211,28 +201,6 @@
 	})
 }
 
-// flagsRule is a placeholder that simply returns the location of the file, the generation of the
-// ninja rules is done in generateHiddenAPIBuildActions.
-func flagsRule(ctx android.SingletonContext) android.Path {
-	outputPath := hiddenAPISingletonPaths(ctx).flags
-	return outputPath
-}
-
-// emptyFlagsRule creates a rule to build an empty hiddenapi-flags.csv, which is needed by master-art-host builds that
-// have a partial manifest without frameworks/base but still need to build a boot image.
-func emptyFlagsRule(ctx android.SingletonContext) android.Path {
-	rule := android.NewRuleBuilder(pctx, ctx)
-
-	outputPath := hiddenAPISingletonPaths(ctx).flags
-
-	rule.Command().Text("rm").Flag("-f").Output(outputPath)
-	rule.Command().Text("touch").Output(outputPath)
-
-	rule.Build("emptyHiddenAPIFlagsFile", "empty hiddenapi flags")
-
-	return outputPath
-}
-
 // tempPathForRestat creates a path of the same type as the supplied type but with a name of
 // <path>.tmp.
 //
diff --git a/java/hiddenapi_singleton_test.go b/java/hiddenapi_singleton_test.go
index 3ab2277..e6b45ac 100644
--- a/java/hiddenapi_singleton_test.go
+++ b/java/hiddenapi_singleton_test.go
@@ -60,10 +60,7 @@
 }
 
 func TestHiddenAPISingletonWithSourceAndPrebuiltPreferredButNoDex(t *testing.T) {
-	expectedErrorMessage :=
-		"hiddenapi has determined that the source module \"foo\" should be ignored as it has been" +
-			" replaced by the prebuilt module \"prebuilt_foo\" but unfortunately it does not provide a" +
-			" suitable boot dex jar"
+	expectedErrorMessage := "module prebuilt_foo{os:android,arch:common} does not provide a dex jar"
 
 	android.GroupFixturePreparers(
 		hiddenApiFixtureFactory,