diff --git a/apex/apex.go b/apex/apex.go
index f95bd05..f7042fc 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -1403,7 +1403,8 @@
 
 type PrebuiltProperties struct {
 	// the path to the prebuilt .apex file to import.
-	Source string `blueprint:"mutated"`
+	Source       string `blueprint:"mutated"`
+	ForceDisable bool   `blueprint:"mutated"`
 
 	Src  *string
 	Arch struct {
@@ -1432,6 +1433,14 @@
 }
 
 func (p *Prebuilt) DepsMutator(ctx android.BottomUpMutatorContext) {
+	if ctx.Config().FlattenApex() && !ctx.Config().UnbundledBuild() && p.prebuilt.SourceExists() {
+		// If the device is configured to use flattened APEX, don't set
+		// p.properties.Source so that the prebuilt module (which is
+		// a non-flattened APEX) is not used.
+		p.properties.ForceDisable = true
+		return
+	}
+
 	// This is called before prebuilt_select and prebuilt_postdeps mutators
 	// The mutators requires that src to be set correctly for each arch so that
 	// arch variants are disabled when src is not provided for the arch.
@@ -1473,6 +1482,10 @@
 }
 
 func (p *Prebuilt) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	if p.properties.ForceDisable {
+		return
+	}
+
 	// TODO(jungjw): Check the key validity.
 	p.inputApex = p.Prebuilt().SingleSourcePath(ctx)
 	p.installDir = android.PathForModuleInstall(ctx, "apex")