first of all these install instructions are overly complicated, just use:
one wild gues would be that the initrd misses the right controller driver for the eMMC in the NUC (though i remember we had a bug and added some, but perhaps the HW evolved and new drivers need to be included) … if the system is in this state do you see anything in /dev/disk/by-label/ when checking from the initramfs shell ?
