Thanks for the 'unbrick' fix a few days back and to all the people who have added their input on this thread. My c10 had been doing the flashing Sony logo thing post-update to 1604... I'd be semi-ok with the update IF Sony's firmware had actually worked as advertised (maybe Sony will release a properly tested firmware that actually makes the device a functional clock/alarm)?
Anyhow for the time being I rolled back to 1526, joined the network, authenticated, pulled down control panel stuff, got the update notice, pulled power, plugged-in power while holding Vol+ to skip update, got to control panel and quickly blocked the device/static IP on my router from reaching the internet. The device has an IP, but can't chat with the Sony servers to say it doesn't have the latest firmware...so no more update notice. I had a Dash clock app and have made that full screen...all has been good for a couple of days. All I have at this time is a clock that does not remind me that I am not connected to a network...which is better than a $200 single purpose "ad" device that not only advertises Sony to me on the screen but also with a bonus flashing Sony logo to boot. The clock function will do...until the device becomes a Chumby.