Summary: Customer did what hardware vendor should have done
The original plan was to order a XPS 15 pre-install with Linux.
Website of Dell has / had it too well hidden,
so we ordered a XPS 15 9570 with MS Windows 10 and installed Linux.
Installed with version 2018-08-06
the non-free firmware is for the wireless network interface card.
The .iso was dd-ed to a usb memory stick.
Upon power-on pressed repeatly F12 to get One-Time Boot Menu
Changed boot mode to
1) Legacy External Device Boot Mode, Secure Boot OFF
Two warning screens/menus followed. Using lot of yellow text
and even red text.
Confirmed both with "Yes, my hardware, my choice of software"
Booted from the usb memory stick ( not from the partition
within the usb memory stick )
Was greeted by the graphical toplevel menu. Did choose 'install'.
Not 'graphical install' to avoid possible issues. The 'graphic
install' might work, it wasn't tested by me.
There was a warning about missing firmware, it could be ignored due
the use of the nonfree included CD image. ( With using the regular
image (also from weekly build 2018-08-06) there was the same warning
with more missing drivers missed, but ignoring that warning did get me
a working WIFI connection. )
The install went fine. Packages being downloaded. The nvme disk being
detected, partitioned, written.
The first reboots weren't succesfull, additional tweaking was needed.
Oh, by the way the firmware has a time sucking (customer insulting) way
of reporting "no boot device was found". It enters selftest mode and
after the plus five minutes test it eventually tells "no boot device".
Aborting the selftest results into a shutdown.
@Dell: Please report "no boot device" without going through selftest
There was no boot device defined. Defined it manually in "BIOS".
Bootsequence, EFI, ... serveral menus ... grubx64.efi
Then it did boot into a black screen. Used usb memory stick again
for booting into rescue mode. `dmesg` reported
[0.799..] ahci 0000:00:17.0: Found 1 remapped NVMe devices.
[0.799..] ahci 0000:00:17.0: Switch your BIOS from RAID to AHCI mode to use
Done under F12 -> OTHER OPTIONS -> BIOS SETUP -> System Configuration -> SATA
The Dell XPS 15 9570 now runs Debian Buster. What works:
* the nice graphical screen
* the NVMe sdd
* and probably more (untested yet)