Ok what I did is first I typed
2. type nvflash --protectoff
3. type -4 -5 -6 780KPI_UnlockedBIOS.rom then I press enter and it pop out the screen like 2 secs and then it disappear , it shows something require but it disappear so fast I wont be able to see whats missing . but I can flash the XOC bios and rev5 bios use this method , so I don't know why rev6 didn't work for me , anyone has idea??