3bar os?

[Redxbob]

Hello all
Where do i go about finding the 3bar os for my 02 silverado ecu pn 411, i cant seem to find an answer to this and i see it asked a few times in searches of this site. Engine is a 2002 5.3 with speed density only and a 3 bar map. I have only the option for 2 bar map and the 3 bar is greyed out. I was told i need the newer os but i cant seem to find it

[Monty]

I have a 2004 silverado 6.0 that has the same problem ...

[Redxbob]

Really? Nobody? Nobody knows how to do this? Or why the 3bar option is greyed out?