Hi there, any luck yet?
I also have the Teracube2e and updates work fine for me. I’m not very happy with the hardware though, but it works (except for GPS) and that’s a different story.
I noticed that I have to remove battery charging cable before restarting, otherwise the restart gets stuck in the loading screen. However powering off by pressing and holding the power button then also worked and after restart the update was installed.
Also a nice trick to accelerate update installation drastically is to keep display awake, as described here: Update takes to much time
Other than that it sounds like a clean fresh install of iodeOS might help? Did you already try the new installer? Installation - iodé
Anyway, good luck!