It only voids the warranty if they can prove it caused the issue. They can try to claim otherwise, but it’s actually illegal for them to do so.
I had Dell try to do this with a laptop with upgraded RAM that had a bad CPU. They said the upgraded RAM caused the issue and the warranty was voided, so I demanded to see the diagnostic logs that showed this (because I had diagnostic logs that showed it was a physical issue with the CPU).
They processed the warranty repair.
As an aside, that was the only time the BSOD was actually useful to me.
It only voids the warranty if they can prove it caused the issue. They can try to claim otherwise, but it’s actually illegal for them to do so.
I had Dell try to do this with a laptop with upgraded RAM that had a bad CPU. They said the upgraded RAM caused the issue and the warranty was voided, so I demanded to see the diagnostic logs that showed this (because I had diagnostic logs that showed it was a physical issue with the CPU).
They processed the warranty repair.
As an aside, that was the only time the BSOD was actually useful to me.