@butch2k I let it run all night long and it finally booted up. Looks like there is some kind of rom scanning or something which takes a hell lot of time.

Looks like there is a regression with XU4. It boots and works fine until i set up external storage (128GB USB3), then on reboot i get stuck on the boot screen (the one with date on bottom left and small logo at bottom center). I did not have this issue with previous versions.
The problem appears both when doing an in place upgrade (in which case it gets stuck after reboot as i had external storage already set up) and with a brand new image (after setting up the storage as external).