This is in your mind. No one is saying that. Cognitive dissonance. This is just your personal struggle to come to the same conclusion.
It took me awhile to believe it too. So I feel your pain brother!
No one wants to believe this. It's not comforting. If anything, I wish we were wrong. But these chips do have bad underfill. That's a fact.
What isn't a fact, and I'm on your side about this, is the idea that defective underfill explains why 90nm RSXs fail. You are correct that VRAM dies, VDDIO balls on the BGA tend to crack, FBVDDQ balls too. VDDC dies from electromigration (both open and short faults). And how many of those faults are actually due to the underfill vs just normal wear and tear that affects all processors is unknown. That's the point you and
@squeept were making. And its a good one.
But the point
@DeadEnd,
@PostalDude__, and I are making is that when you reball a 90nm RSX you are replacing the BGA, but not the bumps. The bumps also "reflow" and can reestablish a broken connection. But as we all know reflows are inferior and prone to cracking sooner. So the reball may appear tk have worked, but because the underfill is still defective, the bumps will eventually fail again...and sooner.
So if, AND ONLY IF, you need to reball (3034/4xxx), it make more sense to replace the 90nm RSX with a NOS 40nm RSX instead of reballing a 90nm with defective underfill. Now that we know how to instruct the SYSCON to bit calibrate the 65nm and 40nm RSX, this is a no brainer. Why the hell not?
I whole heartedly agree! Keep fighting the good fight brother!