diff --git a/mainwindow.cpp b/mainwindow.cpp
index 38f11fa..7791fcb 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -12,7 +12,9 @@ MainWindow::MainWindow(Worker *worker, QWidget *parent)
     : QMainWindow(parent)
     , ui(new Ui::MainWindow)
     , m_worker(worker)
-    , m_width(70) {
+    , m_width(70)
+    , m_progressRunning(false)
+    , m_progressValue(0) {
     ui->setupUi(this);
 
     ui->updateProgress->setRange(0, 100);
@@ -71,11 +73,51 @@ MainWindow::~MainWindow() {
 
 void MainWindow::customEvent(QEvent *event) {
     if (event->type() == ProgressEvent::type()) {
-        int progress = ((ProgressEvent *)(event))->progressPercent();
-        if (progress > 0) {
-            ui->updateProgress->setValue(progress);
+        ProgressEvent *pevent = (ProgressEvent *)event;
+        int const progress = pevent->progressPercent();
+        QObject const *sender = pevent->sender();
+        if (sender == this) {
+            switch(progress) {
+            case 0: {
+                ui->updateProgress->reset();
+            } break;
+            case START_PROGRESS_LOOP: {
+                m_progressRunning = true;
+                ui->updateProgress->reset();
+                m_progressValue = 10;
+                QApplication::postEvent(this, new ProgressEvent(this, m_progressValue));
+            } break;
+            case STOP_PROGRESS_LOOP: {
+                m_progressRunning = false;
+                m_progressValue -= 10;
+                m_worker->setProgress(m_progressValue/10);
+            } break;
+            default: {
+                    if (m_progressRunning) {
+                        m_progressValue = progress;
+                        ui->updateProgress->setValue(progress/10);
+                        QApplication::postEvent(this, new ProgressEvent(this, progress+10));
+                        QThread::msleep(100);
+                    }
+                }
+            }
+        } else
+        if (sender == m_worker) {
+            switch(progress) {
+            case 0: {
+                ui->updateProgress->reset();
+            } break;
+            case START_PROGRESS_LOOP: {
+                QApplication::postEvent(this, new ProgressEvent(this, START_PROGRESS_LOOP));
+            } break;
+            case STOP_PROGRESS_LOOP: {
+                QApplication::postEvent(this, new ProgressEvent(this, STOP_PROGRESS_LOOP));
+            } break;
+            default:{
+                ui->updateProgress->setValue(progress);
+            }}
         } else {
-            ui->updateProgress->reset();
+            qCritical() << "!!! UNKNOWN SENDER !!!";
         }
     }
 }
diff --git a/mainwindow.h b/mainwindow.h
index e71ed78..df47262 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -20,6 +20,11 @@ public:
     MainWindow(Worker *worker, QWidget *parent = nullptr);
     ~MainWindow();
 
+    static const int START_PROGRESS_LOOP = -1;
+    static const int STOP_PROGRESS_LOOP = -2;
+
+    int progressValue() const { return m_progressValue; }
+
 public slots:
     void onAppendText(QString, QString suffix = "");
     void onReplaceLast(QString, QString);
@@ -38,5 +43,7 @@ private:
     int m_width;
     QTimer *m_startTimer;
     QTimer *m_exitTimer;
+    bool m_progressRunning;
+    int m_progressValue;
 };
 #endif // MAINWINDOW_H
diff --git a/progress_event.cpp b/progress_event.cpp
index 4b2c043..8cbf0a0 100644
--- a/progress_event.cpp
+++ b/progress_event.cpp
@@ -2,8 +2,9 @@
 
 QEvent::Type ProgressEvent::customEventType = QEvent::None;
 
-ProgressEvent::ProgressEvent(int progressPercent)
+ProgressEvent::ProgressEvent(QObject const *sender, int progressPercent)
     : QEvent(ProgressEvent::type())
+    , m_sender(sender)
     , m_progressPercent(progressPercent) {
 }
 
diff --git a/progress_event.h b/progress_event.h
index 5b78c0e..e8bd4be 100644
--- a/progress_event.h
+++ b/progress_event.h
@@ -5,12 +5,16 @@
 
 class ProgressEvent : public QEvent {
 
+    QObject const *m_sender;
     int m_progressPercent;
 public:
-    explicit ProgressEvent(int progressPercent);
+    explicit ProgressEvent(QObject const *sender, int progressPercent);
     virtual ~ProgressEvent();
     static QEvent::Type type();
 
+    QObject const *sender() { return m_sender; }
+    QObject const *sender() const { return m_sender; }
+
     void setProgress(int progressPercent) { m_progressPercent = progressPercent; }
     int progressPercent() { return m_progressPercent; }
     int progressPercent() const { return m_progressPercent; }
diff --git a/worker.cpp b/worker.cpp
index b45efdb..4b2c72e 100644
--- a/worker.cpp
+++ b/worker.cpp
@@ -68,7 +68,8 @@ Worker::Worker(hwinf *hw,
   , m_waitForNewUpdates(this)
   , m_filesToUpdate()
   , m_updateProcessRunning(false)
-  , m_returnCode(0) {
+  , m_returnCode(0)
+  , m_progressValue{0} {
 
     QDir::setCurrent(m_workingDirectory);
 
@@ -116,10 +117,19 @@ Worker::~Worker() {
 
 void Worker::setProgress(int progress) {
     if (m_mainWindow) {
-        QApplication::postEvent(m_mainWindow, new ProgressEvent(progress));
+        m_progressValue = progress;
+        QApplication::postEvent(m_mainWindow, new ProgressEvent(this, progress));
     }
 }
 
+void Worker::startProgressLoop() {
+    QApplication::postEvent(m_mainWindow, new ProgressEvent(this, MainWindow::START_PROGRESS_LOOP));
+}
+
+void Worker::stopProgressLoop() {
+    QApplication::postEvent(m_mainWindow, new ProgressEvent(this, MainWindow::STOP_PROGRESS_LOOP));
+}
+
 static std::once_flag once;
 void Worker::update() {
     // user should not start the update process several times
@@ -130,17 +140,27 @@ void Worker::privateUpdate() {
     QPushButton *start = qobject_cast<QPushButton *>(QObject::sender());
     start->setEnabled(false);
 
-    //emit appendText("\nConnecting backend ...");
-    //
-    //for (int i=0;i <= 100; ++i) {
-    //    setProgress(i);
-    //    QThread::msleep(100);
-    //}
-    //emit replaceLast("Connecting backend ...", UPDATE_STEP_OK);
-    //emit appendText(QString("UPDATE "), UPDATE_STEP_SUCCESS);
-    //emit appendText(QString("UPDATE "), UPDATE_STEP_FAIL);
-    // setProgress(0);
-    // return;
+#if 0
+    emit appendText("\nConnecting backend ...");
+
+    for (int i=0;i <= 100; ++i) {
+        setProgress(i);
+        QThread::msleep(100);
+    }
+    emit replaceLast("Connecting backend ...", UPDATE_STEP_OK);
+    emit appendText(QString("UPDATE "), UPDATE_STEP_SUCCESS);
+    emit appendText(QString("UPDATE "), UPDATE_STEP_FAIL);
+    setProgress(0);
+
+    startProgressLoop();
+    QThread::sleep(5); // long running process
+    stopProgressLoop();
+    for (int i=m_mainWindow->progressValue()/10; i <= 100; ++i) {
+        setProgress(i);
+        QThread::msleep(100);
+    }
+    return;
+#endif
 
     emit stopStartTimer();
     emit disableExit();
diff --git a/worker.h b/worker.h
index 5daea58..2a60b0c 100644
--- a/worker.h
+++ b/worker.h
@@ -126,6 +126,7 @@ class Worker : public QObject {
     int m_returnCode;
 
     MainWindow *m_mainWindow;
+    int m_progressValue;
 
     bool executeOpkgCommand(QString opkgCommand);
     QString getOsVersion() const;
@@ -138,8 +139,6 @@ class Worker : public QObject {
 
     qint64 getFileSize(QString const &fileName) const;
 
-    void setProgress(int progress);
-
 public:
     static const QString UPDATE_STEP_OK;
     static const QString UPDATE_STEP_DONE;
@@ -159,6 +158,7 @@ public:
     ~Worker();
 
     void setMainWindow(MainWindow *mainWindow) { m_mainWindow = mainWindow; }
+    void setProgress(int progress);
 
     IsmasClient &getIsmasClient() { return m_ismasClient; }
     IsmasClient const &getIsmasClient() const { return m_ismasClient; }
@@ -205,6 +205,8 @@ private:
     PSAInstalled getPSAInstalled();
     QString sendCmdSendVersionToIsmas();
     void privateUpdate();
+    void startProgressLoop();
+    void stopProgressLoop();
 };
 
 #endif // WORKER_H_INCLUDED