diff --git a/src/rollup-vsix-plugin.ts b/src/rollup-vsix-plugin.ts
index 262514c7..c8918db7 100644
--- a/src/rollup-vsix-plugin.ts
+++ b/src/rollup-vsix-plugin.ts
@@ -12,7 +12,7 @@ interface Options {
   exclude?: FilterPattern
   rollupPlugins?: InputPluginOption[]
   transformManifest?: (manifest: IExtensionManifest) => IExtensionManifest
-  getAdditionalResources?: (manifest: IExtensionManifest) => Promise<ExtensionResource[]>
+  getAdditionalResources?: (manifest: IExtensionManifest, getFileContent: (path: string) => Promise<Buffer>, listFiles: (path: string) => Promise<string[]>) => Promise<ExtensionResource[]>
 }
 
 function read (stream: Readable): Promise<Buffer> {
@@ -86,15 +86,15 @@ export default function plugin ({
       const getFileContent = async (filePath: string): Promise<Buffer> => {
         return readFileSync(filePath)
       }
-      const listFiles = async (path: string) => {
-        return (vsixFS.readdirSync(path) as string[])
+      const listFiles = async (filePath: string) => {
+        return (vsixFS.readdirSync(path.join('/', filePath)) as string[])
       }
       const extensionResources = (await extractResourcesFromExtensionManifest(manifest, getFileContent, listFiles))
         .filter(resource => vsixFS.existsSync(path.join('/', resource.realPath ?? resource.path)))
 
       const resources = [
         ...extensionResources,
-        ...await getAdditionalResources(manifest)
+        ...await getAdditionalResources(manifest, getFileContent, listFiles)
       ]
 
       const pathMapping = (await Promise.all(resources.map(async resource => {