diff --git a/src/index.ts b/src/index.ts
index 6109424..16b567e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -241,7 +241,7 @@ export default class Updater {
                 // write file length
                 return new Promise((resolve, reject) => {
                         // set mtu
-                        this.bleObject.requestMtu(this.bleDeviceId, this._packetSize, (mtu: number) => { this._packetSize = mtu}, () =>{ })
+                        this.bleObject.requestMtu(this.bleDeviceId, this._packetSize, (mtu: number) => { this._packetSize = mtu}, () =>{});
                         // start notify
                         this.bleObject.startNotification(this.bleDeviceId, this._updaterServiceUUID, this._updaterCommandCharacterisitcUUID,
                                 (rawData: ArrayBuffer): void => {
@@ -278,7 +278,7 @@ export default class Updater {
                                                 }
                                         } else if (dataView[0] == 15) {
                                                 // error cmd
-                                                progressCallback(`Error on remote`);
+                                                progressCallback(`Error on remote: ${this._fileProgress} / ${this._fileSize}`);
                                                 reject("Error on remote");
                                         } else if (dataView[0] == 0) {
                                                 // ignore no command