MacRumors says it's obtained an internal Apple Authorized Service Provider document that reportedly details a known issue with some iPhone 7 and iPhone 7 Plus handsets -- one where the mic stops working during phone calls and FaceTime video chats, and where the speakerphone button might stop working.
According to a source who spoke to AppleInsider, it's an extremely rare issue, and one that might be easy to fix. Apple technicians are reportedly being instructed to disconnect Bluetooth headsets or other audio accessories first to see if that solves the problem. (You might as well do that yourself.)
But if that speakerphone button is grayed out, there might be a hidden message in the diagnostics menu that reads "device could not detect dock" or "accessory not supported," at which point Apple can try to repair your phone -- and if you're not covered under warranty, MacRumors says the document allows Apple service providers to make a warranty exception.
Potentially, you could get it fixed for free.
Apple didn't immediately respond to a request for comment.