Sorry I don’t have a solution for you but I have a Zulu (not sure what version) that I Bluetooth to my iPhone Xs and talk away happily with a 912 on full noise in my Flysynthesis Storch. I have even successfully FaceTimed my son so he could see what was going on. Have made a phone call with a passenger in the plane and they could hear me but not the phone call (as expected). Have a microair PM501 intercom. I sometimes have had a problem with a plugged in headset (dodgy connection I think) that the phone uses it's own microphone rather than the headset mic which gives crappy audio to the other end. As I Bluetooth in the plane this has never been a problem. Bluetooth also gives me tunes while I fly. ??