I can also confirm that this UNBRICK fix will allow the 1604 firmware update to install again--which then promptly fails to work as usual, with the flashing SONY logo. So that update is a big mess. Anybody know why it fails on so many devices?
We don't know why it fails, and why only on some devices, and at this point, I don't think we're not going to waste any effort investigating. We did just enough research to create this unbricking hack, which was a unnecessary and unwelcome distraction from our larger project for support of the dash.
I've seen similar failures when creating an OTA update during development in the past, however, at least at Chumby, we'd never have released such an update without intensive testing. It's extremely unlikely we'd have released one in this condition. If somehow we had, we would have pulled the update at the very first report of a failure the field, and sought to undo the damage.