The latest update from umbrel prevents you from doing that. You have to install it from a friggin iso. I'm so pissed about that. 

The issue is that I'm trying to run it via a proxmox server, and I can't get the VM I've set up for umbrel to boot from the formatted USB drive. Like I said elsewhere, I like to make my life really hard sometimes. 🫣😅😱👀🙄