Hey there and sorry for asking stupid questions already. I faced the same issue like some others being stucked to the starting screen of my Umbrel on a Raspi 4. I managed to reboot with the ssh command and finally reflashed my sd card and am almost back to normal. The chain synced again and my lightning are also back to normal.
However, my Specter app still in the endless loop of starting so I decided to uninstall/reinstall (I have the needed backup of Specter). Specter back as well but - oh crap - it almost looks like a different app after the huge update. My only problem remaining is the connection to Bitcoin core on my Raspi4. I tried several things like getting the credentials from Bitcoin node (RPC local network) but I failed with everything I tried.
Anyone managed to establish a connection and could help me with my issue? Highly appreciated & thank you so much!
My versions: Umbrel 0.5.4
Specter: 2.0.2
Hosts I tried:
http://umbrel.local
http://IP address
http://localhost
Name: Bitcoin Core
User: umbrel
PW: given PW