My SP4 updated this past weekend and now I see the screen flickering. After a bit of searching, I found that some SP4 devices have this issue. I can't see if it's defective, or a result of the update. It was purchased in 2015, so I would imagine it's well past the warranty. Is MS offering a replacement for this, or should expect that this thing will become unusable? I never saw the flickering prior to the update, so I don't know if it's a result of that or just a coincidence. Thanks.