I have also been having that issue, but I haven't been able to find out what is causing it. It appears it's an issue with the Gnome version, as I flashed the Plasma version to the same card and it works just fine.
I believe the reason it won't boot is because it moves quite a few of the essential files before beginning the upgrade. If I try to open any application before powering it off, such as settings or the terminal, it gives me a message saying the application isn't found.
I believe the reason it won't boot is because it moves quite a few of the essential files before beginning the upgrade. If I try to open any application before powering it off, such as settings or the terminal, it gives me a message saying the application isn't found.