so I'm on macOS 15.4 in Germany, and finally managed to trigger the firmware update. In both iOS and macOS settings, it shows the firmware as 7E101.
Now I want to check out the USB-C thing, but does it work at all? It appears not.
I connect a USB-C cable to my MacBook Pro and then:
If Bluetooth is enabled, the APM will connect via Bluetooth. I can play sound to them, and in Audio Midi Setup the mic input and the stereo output is shown, but with a Bluetooth icon.
If I disable Bluetooth, they disconnect, no sound, not visible in Audio Midi Setup etc...
also if sound is playing through APM, and I pull out the USB cable, nothing happens, the sound keeps playing through Bluetooth.
on iOS pretty much the same, I did get a notification there to connect a USB-C cable for lossless, but it appears the only connection happening is via Bluetooth.
I did reset the APM, and restarted the Mac and the iPhone, but it doesn't seem like there is an actual audio connection happening at all through USB. weird? I think so.
edit: after several times unplugging replugging, it nows shows an USB-Audio logo, so seems to work. It appears it's meant to work together with the BT connection and will auto-enable the USB stream if available. in Audio Midi Settings, I only see Airpods Max USB-C if BT is disabled. Otherwise macOS seems to stick the USB stream into the audio device that appears as the normal APM with the BT icon.