Just jumping in to say I had this exact same issue on a fresh box that I’ve been trying to get set up.
When I use the image provided by the downloader on the CE homepage, it boot loops the same way you’re describing. Hits the Homatics splash, then seems to power cycle over and over. A14 boots as normal if I unplug the USB.
Tested the stable on multiple USBs, with no success booting using the Reboot app, or the reset button.
After that, I tried the latest nightly (as of a week ago) which I was able to boot without any issues, but on this build, I wasn’t able to see any Dolby Vision settings.
I followed some advice and ran an update using the CPM build, but still wasn’t able to see the DV settings despite the System Info screen reporting my TV as DV compatible. When I played the DV test videos, my TV reported the content as HDR10, not DV.
I’ll try some other build combos again today… If I have any luck, I’ll pop something on this thread. Otherwise if anyone has any advice, I’d be happy to try anything…