I'm not sure what the right way to install Android 6 but this is the broad outline of the steps I performed. Also I have no idea what the long term repercussions are. Good luck to me.
WARNING you are on your own if you decide to do anything I describe hereGoogle's instructions make certain recommendations:
- latest Android SDK
- means installing the Android Developer Studio; and if you're like me and you refuse to install Java then you'll need version 7 or better
- Latest Android Image
Now for the phone:
- put the Nexus 6 in developer mode
- enable OEM unlock
- power-off the phone
- connect the phone to your computer
- quick boot the phone (volume down+power)
- OEM unlock
- select YES; then press the power button (WARNING; going to delete everything and reboot)
- once the phone reboots you'll have to
- unzip the Android 6 image
- make sure fastboot is in the path
- run flash-all.sh
- (I had run out of the house before this step finished so I do not know if there was a reboot. I imagine there was)
- now do a normal init.
So now things are wonky. And have me bothered.
- the phone would not lock without a purge
- the phone remained in developer mode (turning it off was ok, but still squirrely)
- the phone also had OEM unlock enabled (could not disable without a purge)
- I'm pretty certain everything restored ok... it took almost 60 minutes to restore my apps. Seemed kinda long.
- I think my biggest concern is that the ATT splash page is still running and the dancing balls is still booting the firmware instead of the spinning circles.
So I do not know if I've created a franken-phone or if it's ready for primetime.