Let me clarify. I am getting Sentry mode recording just fine. The DashCam icon is not showing up at the top of the screen
Sentry mode can operate without the USB drive, but no footage is saved locally as far we know. Tesla mentions uploading alarm state footage for backup but I’ve not heard of anyone actually getting it from them. For your purposes, no dashcam icon means you are not getting local recordings from sentry either.
That would have been my assumption as well, but I am getting sentry mode recordings. That is why I asked
Sentry does not turn on recording when driving. Because sentry doesn't work when driving. Recording when driving is enabled automatically when a properly configure USB device is installed