please, is possible add DVD-RAM feature to this drive with firmware reflashing?
Usually, GWA drives don’t come with DVD-RAM support, GSA ones do. I am not sure how similar the components inside the GSA-4165B and GWA-4165B are. I suppose if they are the same internally you might be able to add the feature by using GSA firmware. The problem is that GSA firmware does not work on GWA drives.