diff --git a/packages/router/upgrade/src/upgrade.ts b/packages/router/upgrade/src/upgrade.ts
index 82336fd35d..c76fbabb1a 100644
--- a/packages/router/upgrade/src/upgrade.ts
+++ b/packages/router/upgrade/src/upgrade.ts
@@ -38,7 +38,7 @@ import {UpgradeModule} from '@angular/upgrade/static';
 export const RouterUpgradeInitializer = {
   provide: APP_BOOTSTRAP_LISTENER,
   multi: true,
-  useFactory: locationSyncBootstrapListener,
+  useFactory: locationSyncBootstrapListener as(ngUpgrade: UpgradeModule) => () => void,
   deps: [UpgradeModule]
 };
 
diff --git a/tools/public_api_guard/router/upgrade.d.ts b/tools/public_api_guard/router/upgrade.d.ts
index 5f51dd10ca..2fd7d62113 100644
--- a/tools/public_api_guard/router/upgrade.d.ts
+++ b/tools/public_api_guard/router/upgrade.d.ts
@@ -2,7 +2,7 @@
 export declare const RouterUpgradeInitializer: {
     provide: InjectionToken<((compRef: ComponentRef<any>) => void)[]>;
     multi: boolean;
-    useFactory: typeof locationSyncBootstrapListener;
+    useFactory: (ngUpgrade: UpgradeModule) => () => void;
     deps: (typeof UpgradeModule)[];
 };