thanks for the reply, you inspired me to grab Ubuntu 18.04, put it on a usb key and boot my 5530, but alas it doesn't recognize the NVMe disk. There's a single line from dmesg about remmapping a NVMe disk, but Nothing on fdisk -l.

What version of Ubuntu are you running? Is it produced by Dell or the generic release?

edit nevermind I found a fix: in the BIOS (F2 while booting), I needed to set System Config -> SATA Operation -> AHCI. With that, the nvme is found just fine.