diff --git a/src/index.ts b/src/index.ts
index 8eddcf4..96d2e0f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -288,7 +288,7 @@ export default class Updater {
                                         else {
                                                 // should be the file progress
                                                 let fileProgressView = new Uint32Array(rawData);
-                                                this._fileProgress += (dataView[3] << 24) |
+                                                this._fileProgress = (dataView[3] << 24) |
                                                                         (dataView[2] << 16) |
                                                                         (dataView[1] << 8) | dataView[0];
                                                 this.sendNextPacket();