I am trying to figure out how to change my Base OS. Is this possible and if so how does one go about doing it? I have a 2001 P01 ecu that I changed to a 2 bar enhanced for my truck. It was a 12208322 base OS and now is 1253012 OS. I would like to add the flex fuel ability for a P01 out of a 2002 ecu that has a base OS of 12216125. I understand If I need to license the tune file I want to use with the flex OS. But even if I do can I put that OS on my current ecu using a write entire? or can this ecu not handle it? thanks.