Yes, customers have been successful with the "rollback" (I don't like the word downgrade ). Like with anything you'll typically hear much more about when it doesn't work versus when it does work. ETM does post some suggestions about what will make the rollback more successful, but basically says put your phone in airplane mode, then turn on BT, and make sure the screen sleep is turned off (so the screen stays on all the time).
That‘s good to hear. I’ve asked this same question several times in this thread and hadn’t heard any definitive replies of successful “rollbacks” from any end users.