My searching turned up mixed results as to whether Slackware 15.0 (-stable branch) supports NVMe drives, so I decided to experiment. Yesterday I was able to successfully install from a Slackware 15.0 USB on a Dell XPS 13 laptop [ca. 2017, with UEFI] and a Crucial P3 1TB NVMe drive [model # CT1000P3SSD8] and 8 GB of RAM. I used GRUB rather than eLILO.
(I'm a new Slackware user, so I might not have done things the "correct" way and just was extremely lucky.)

I'm posting this in case it might give you an alternative approach ...
The Crucial NVMe has a gpt partition table, and I created a /boot/efi partition [fat32 file system] of 619 MiB with flags of "boot,esp". It was identified as /dev/nvme0n1p1.
I pre-partitioned the drive with GParted (from a Live USB session on Puppy Linux). I created a root partition of 55 GiB [ext4] (/dev/nvme0n1p2), a /home partition of 824 GiB [ext4] (/dev/nvme0n1p4) and a swap partition of 2.79 GiB [linux-swap] (/dev/nvmen0n1p3).
I skipped using the Slackware installer's built-in partitioner(s) and went directly to the "setup" stage of the installation. As I proceeded through the installation steps, the installer correctly identified/recognized all my partitions.
I skipped the step of installing LILO and also skipped installing eLILO (because I wanted GRUB as the bootloader).
I followed the procedure demonstrated by OldTechBloke (R.I.P., Steve) in his YouTube video. The segment relating to GRUB installation runs from minute 21:06 until 24:49:
https://www.youtube.com/watch?v=0yoP9xnh4jI
OldTechBloke. "
Slackware 15 is Released! [...]" 5 Feb. 2022.
After typing the
command, I was hopeful of success when I saw that /boot/efi was recognized on /dev/nvme0n1p1. I crossed my fingers and continued ...
The sequence of commands for this part of the procedure is:
Code:
# mount
# chroot /mnt /bin/bash
# source /etc/profile
# grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=grub
# grub-mkconfig -o /boot/grub/grub.cfg
(OldTechBloke reminds viewers that the "grub-mkconfig" command must be run every time the kernel is updated.)
I was pleasantly surprised that when I completed the installation and rebooted, the GRUB screen displayed and I booted into Slackware with no problems -- no kernel panic, no halting at a " grub> " prompt. (Again, maybe this is a case of beginner's luck.)
HTH and Good luck.
P.S.
Output from fdisk and /etc/fstab:
Code:
root@darkstar:~# fdisk -l
Disk /dev/nvme0n1: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: CT1000P3SSD8
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: F56B37DE-BFD4-480F-9EEE-E6E71B43A8EA
Device Start End Sectors Size Type
/dev/nvme0n1p1 2048 1271807 1269760 620M EFI System
/dev/nvme0n1p2 1271808 118458367 117186560 55.9G Linux filesystem
/dev/nvme0n1p3 118458368 124317695 5859328 2.8G Linux swap
/dev/nvme0n1p4 124317696 1882130431 1757812736 838.2G Linux filesystem
/etc/fstab:
Code:
/dev/nvme0n1p3 swap swap defaults 0 0
/dev/nvme0n1p2 / ext4 defaults 1 1
/dev/nvme0n1p4 /home ext4 defaults 1 2
/dev/nvme0n1p1 /boot/efi vfat defaults 1 0
#/dev/cdrom /mnt/cdrom auto noauto,owner,ro,comment=x-gvfs-show 0 0
/dev/fd0 /mnt/floppy auto noauto,owner 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
proc /proc proc defaults 0 0
tmpfs /dev/shm tmpfs nosuid,nodev,noexec 0 0