When I had unpacked my new FP6 last week and wanted to open the sim tray with that charming tiny tool I pushed it for a moment in the microphone’s hole, which is right next to the tray’s one …..
I haven’t had complaints from people on the phone, nor have I heard any bad sounds myself in my own voice which I recorded, but could anything have happened anyway? I have looked for detailed technical pictures but didn’t find any with the mike.
I think you cannot do more than testing it – which you did. There are also built-in hardware tests, either to be found in the My Fairphone app or by dialling * # * # 2 8 8 6 # * # * However, the tests do not do anything really different than what you already did with the voice recorder.
From what I know, Fairphone has not yet released schematics for the FP6 (they did for the FP4 and the FP5, but never at launch, but a while later).