My Nucleus + crashed a while ago. I fiddled around and noticed that it would POST and boot to bios without an NVMe SSD installed. I tried several NVMe’s including the Transcend model recommended by Roon.
I assume that there must be a controller failure of some sort.
I installed a 3.5" SSD using the SATA port and successfully installed ROCK. I don’t use internal storage in my Nucleus.
Maybe this will be of interest to other users experiencing issues with their Nucleuses (nuclei?)