After seeing RCS start working by granting com.google.android.gms READ_DEVICE_IDENTIFIER I thought perhaps I could get Visual Voicemail on Google Phone to start working. (It wouldn't load anything in the past).
This time before changing permissions it actually showed a new voicemail, however when I hit "play" it says loading and then fails.
I checked permissions for com.google.android.dialer (Google Phone) via ADB I found that both READ_DEVICE_IDENTIFIER and USE_ICC_AUTH_WITH_DEVICE_IDENTIFIER had recently been "rejected". I was able to grant it READ_DEVICE_IDENTIFIER, however that didn't get it working. When I try to grant USE_ICC_AUTH_WITH_DEVICE_IDENTIFIER permission there is no error, however it doesn't change from "default". Is this locked down somehow?
Can anyone comment on how the built in dialer authenticates with a network provider? Being that it shows a voicemail I'm thinking it could work, but somehow the app isn't able to authenticate (my speculation).