My phone's suddenly developed a problem with Siri. It hears nothing through my headset microphone if and only if Siri is opened using the headset remote button. If I open Siri with the Home button, it hears through the headset mic just fine. Everything else about Siri works just fine. There is no problem using my car's bluetooth to invoke Siri. There is also no physical problem with the microphone (I have used multiple known-working headsets, I can record voice memos over the headset mic, and I can even use Siri with the headset mic if I open Siri using the Home button instead of the remote button. Might seem like a minor thing, but I ride 10-20 miles on my bicycle every day, so I need to be able to use Siri without access to the phone.