App starts after boot then is minimized

Question

I am developing an app and I need it to start after boot the device or after mounting the sdcard. This has been done using a receiver in manifest and a class that extends BroadcastReceiver.

Fragment of AndroidManifest.xml

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission  android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<receiver android:name="util.MediaMountedReceiver" android:enabled="true"
        android:exported="false" >
    <intent-filter>
        <action android:name="android.intent.action.MEDIA_MOUNTED" />
        <data android:scheme="file"/>
    </intent-filter>
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
    </intent-filter>
</receiver>

Class MediaMountedReceiver

public class MediaMountedReceiver extends BroadcastReceiver{

    SharedPreferences sharedPref = null;

    @Override
    public void onReceive(Context context, Intent intent) {

        sharedPref = PreferenceManager.getDefaultSharedPreferences(context);        

        /** Verifica se é para iniciar automático ou não */
        if(sharedPref.getBoolean(SettingsFragment.KEY_PREF_STARTUP_AUTO, false)){
            Intent i = new Intent(context,  PlayerScreen.class);  
            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(i);
        }
    }
}

In almost all devices I tested functioned normally except one mini pc android.

Conf. the device: Android 4.1.1 Kernel Version 3.0.8 + rk30sdk-eng4.1.1 JRO03H

In this device after booting the app is opened and following is minimized. I believe it is a configuration problem device itself since I have other similar features but with different versions of android.