diff --git a/src/api/filesystem.ts b/src/api/filesystem.ts
index 6077a0f..9471487 100644
--- a/src/api/filesystem.ts
+++ b/src/api/filesystem.ts
@@ -20,8 +20,14 @@ export class BadgeFileSystemApi {
     textEncoder = new TextEncoder();
     textDecoder = new TextDecoder();
 
-    /** Lists entries in the folder given by `path` */
-    async list(path: string): Promise<FileListing[]> {
+    /**
+     * Lists entries in the folder given by `path`
+     * @param path default: `/internal`
+     */
+    async list(path: string = '/internal'): Promise<FileListing[]> {
+        if (path == '') {
+            throw Error('Path must not be empty');
+        }
         let pathEncoded = this.textEncoder.encode(path);
         let data: ArrayBuffer = await this.transaction(BadgeUSB.PROTOCOL_COMMAND_FILESYSTEM_LIST, pathEncoded, 4000);
 
diff --git a/src/badge-api.ts b/src/badge-api.ts
index df504dc..05b8efd 100644
--- a/src/badge-api.ts
+++ b/src/badge-api.ts
@@ -3,10 +3,10 @@
  * @author Reinier van der Leer
  */
 
+import { BadgeUSB, TransactionArgs } from "./badge-usb";
 import { BadgeFileSystemApi } from "./api/filesystem";
 import { BadgeAppFSApi } from "./api/appfs";
 import { BadgeNVSApi } from "./api/nvs";
-import { BadgeUSB } from "./badge-usb";
 
 export type ProgressCallback = (status: string, progressPercent: number) => void;
 
@@ -54,15 +54,19 @@ export class BadgeAPI {
 
 
     /*** Filesystem API ***/
-    public fileSystem = new BadgeFileSystemApi(this.transaction);
+    public fileSystem = new BadgeFileSystemApi(
+        (...args: TransactionArgs) => this.transaction(...args),
+    );
 
     /*** AppFS API ***/
     public appFS = new BadgeAppFSApi(
         this.fileSystem,
         this.disconnect,
-        this.transaction,
+        (...args: TransactionArgs) => this.transaction(...args),
     );
 
     /*** NVS API */
-    public nvs = new BadgeNVSApi(this.transaction);
+    public nvs = new BadgeNVSApi(
+        (...args: TransactionArgs) => this.transaction(...args),
+    );
 }
diff --git a/src/badge-usb.ts b/src/badge-usb.ts
index e8fc4dd..6b9b6ec 100644
--- a/src/badge-usb.ts
+++ b/src/badge-usb.ts
@@ -471,7 +471,7 @@ export class BadgeUSB {
                 dataView, identifier, magic,
                 type: responseType,
                 payload: {
-                    buffer,
+                    buffer: payload,
                     crc: payloadCRC,
                     declaredLength: payloadLength,
                 },
@@ -485,6 +485,8 @@ export class BadgeUSB {
     }
 }
 
+export type TransactionArgs = Parameters<BadgeUSB['transaction']>;
+
 class TransactionPromise extends Promise<TransactionResponse> {
     resolve: (value: TransactionResponse | PromiseLike<TransactionResponse>) => void;
     reject: (reason: TransactionResponse | Error) => void;