Posting this as assistance for anyone else that brain farts....

Got a new motherboard (side note: Asus' BIOS UI BLOWS CHUNKS) and had a time getting Slackware 15 to boot off of it.

Couldn't find the boot settings to set UEFI/Legacy or the device priorities...

Installed Slackware 15 and it detected EFI so it it installed elilo. Wouldn't boot. Created a USB boot drive and it booted fine from that. Used it to reconfigure elilo... Still wouldn't boot. Tried setting up lilo, still no boot.

Installed grub and that worked... Hated that I couldn't get lilo or elilo so I took another whack at it

I FINALLY found the EFI/Legacy setting and set it to legacy and wiped the disk and reinstalled fresh. Slackware detected legacy and installed lilo. Wouldn't boot.

Repeated but with BIOS set to UEFI & Legacy, Slackware detected EFI again and installed elilo but wouldn't boot.

Then I realised that I fdisked the partitions and not gdisked them....

Set the BIOS to UEFI ONLY, wiped the disk, gdisk and reinstalled fresh.

Slackware detected EFI again and SAID that it installed elilo butwhen I booted, it came up with "GRUB" and halted. Booted from the USB stick, messed around with grub-mkconfig.... Messed around with eliloconfig... Both complained and failed.

THEN IT HIT ME- I forgot to add the EFI partition to the disk.

Repartitioned the swap and added an EFI partition (to the end of the disk). Re-installed and it works fine now.

What I learned from this-
1) DON'T FORGET to add an EFI partiton.
2) Grub will boot an efi machine from a non-GPT partition.
3) Slackware (unlike old posts that I read) now supports NVMe drives, no problems.
4) Asus' legacy support is broken.
5) Asus' BIOS UI blows ass. (The boot setup is 3 tabs deep, the last one called CMS Configuration)

I'm also happy to report that Slackware 15 supported the new board's (Asus ROG Ryzen) video, audio, and ethernet chipset with no problems. I usually have to fight with one of these with a brand new board.

Yeah while ASUS hardware side is usually fine, they have their own view to the EFI config lol, and that has not changed since at least 2014.
elilo may not work in usb installer with their newer boards (in my experience)
efibootmgr is useful with ASUS mobos...

I believe you.

I'm happy to report that elilo (and USB boot) works fine on a ASUS ROG Strix B550-F if you create an EFI partition.

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I didn't see which Asus board you got or even whether it's Intel or AMD but I haven't had any of your difficulties with my Asus ROG Maximus XII Hero Intel board. It's only 10th Gen but will apparently support 11th Gen with Asus's version of the Z470 chipset. It did take me a little while to realize CSM was Legacy Boot but only a few minutes since it was on the "Boot" tab and one of the top menu items. My system has 3 NVME drives and I'm not overly pleased with shared PCIe implementation slowing one of them down some, but that may improve when I get an 112th Gen CPU that supports PCIe 4 instead of just 3.

My system has around a dozen operating systems on it both EFI and Legacy boot, including an updated v 12.2 Slackware, a 13.37, several 15.0, OpenSuse and one other linux distro test partition, and ahighly neglected Windows install, but all boot with Boot Order Menu for Legacy and Removable and rEFInd for all the modern booters. It's also pretty heavily overclocked with 10 fans all manually configured. I'm not certain if my USB 3 is setup properly but I've only recently felt any need to mess with it.

If your mobo is newer than mine maybe consider checking for BIOS upgrades. I've updated mine twice and the built in Asus Updater worked perfectly.

ASUS ROG Strix B550-F (AMD)

LILO doesn't work on some NVME drives for cases GRUB2 does.

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I acquired a new laptop, a Dell 7610 series, and I had to go the GRUB route as well. As an added twist, this laptop only supports UEFI booting.

1 members found this post helpful.

Maybe the Slackware gods will add a new menu to the setup-

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