I replaced the speakers on my 15" MBP 2015 yesterday, and when all done, I found this small silver colored sponge (see photo) had fallen off the logic board, but I'm not sure where it fell off. There were a couple of those on the board, apparently serving as some type of a cover over screw heads. But the material is curious, if it's just a cover (why not just use rubber). Anyone know what it does? Thanks.
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Oh, one more thing. There is a small triangular rubber flap that covers a set of screws (see circled area in photo). There are two, one on each side of the laptop. I'm missing one. It's not critical, is it? I put a piece of electrical tape over the missing one.
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Thanks!