Figured out how to update the Chromecast ultra firmware (i think). I joined the preview program in the settings, then pulled power and started again a bunch of times. Now I got
The original Chromecast now works with Spotify
How to Root Your Chromecast « Cord Cutters :: Gadget Hacks
how to update chromecast manually Archives - Switched On Network
Google drops support for original Chromecast
How to Get Firmware Updates on Chromecast with Google TV - YouTube
Google ends support for Chromecast 1st generation | Gagadget.com
This Google Firmware Update Brings Stadia Support To Existing Chromecast Ultras | HotHardware
Chromecast - How to Update Firmware ! - YouTube
Why It Might be Time to Update Your Old Chromecast | Lifehacker
How to Update Chromecast Firmware to the Latest Version - TechOwns
Google Cast Has a Preview Program You Can Enter Right Now (Updated)
How To Force Chromecast To Update
Google Chromecast firmware update failing or stuck at 0% for many
How to Update Chromecast Firmware
Device Firmware Updater | Hubitat Documentation
How to Update Chromecast
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How to Update Chromecast
Chromecast with Google TV gets a firmware update to improve Dolby Vision playback and storage | What Hi-Fi?
How to Update Firmware in Chromecast ! - YouTube
How To Update Chromecast Firmware | Robots.net
Chromecast with Google TV update adds a ton of new features