You can find the rev 5 ROM here (search for "game firmware updates")
http://www.pinrepair.com/sys3/index.htm
Known and Improved bug fix from #743/2
* Fixed power on machine from hang getting tilt messageses
* Fixed 2 tilt warnings ( Tilt Witch ferme, something about "Gesshlossen"
* Fixed Better count on drainet balls/multiball (still some bugs yet)