OK 1604 bricks the unit. It removes the control panel completely and leaves you with just a clock. No weather, nothing.
I have 3 (c10) dash units, 2 are hooked up. One was on a more recent firmware than 1526, I updated. Alarm clock. I rolled it back to 1526, still getting push notifications to "update" to 1604. What I found was interesting was that the push notification doesn't interfere/suspend with any functionality, it just obscures the screen. There is no option to decline. I'm going to call them tomorrow to complain.
The other 1 I have hooked up I haven't received any push notifications. AFAIK that one bricked months ago and I had to update it via USB with what I presume are 1526 drivers. I used the same one to update this one.
So is this chumby update software available yet? I assume if it can hook into the 1526 or is custom firmware we're good. I liked the star trek-y looking control panel with the archer clock
I'm also posting on the subreddit btw.