Arch Linux

pgoetz

Member

From: Austin, Texas

Registered: 2014-02-21

Posts: 355

SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

I'm in the process of trying to re-install an 8-year-old Supermicro rackmount server which was running Arch linux previously.

When I boot from the Arch ISO, I get the legacy menu even though this system only supports EFI, and if I proceed with the boot, it boots in legacy mode (i.e. no /sys/firmware/efi/efivars).

I can work around this, but I've been having various strange boot (or I should say failure to boot) issues with Arch ISOs for months, when prior to this year it was always rock solid and never failed to boot, so I'm trying to get to the bottom of why this is happening.

Also, I say I can work around this, but then I couldn't get efibootmgr to return results after installing it in the arch-chroot, and then ran into other oddball issues like it refused to recognize / configured as an md raid. (Yes, I remembered to add mdadm_udev to /etc/mkinitcpio.conf and rebuild initramfs.)

Last edited by pgoetz (2024-10-01 20:35:19)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 22,844

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

I'm pretty sure the boards that truly "only" have EFI support are in quite the minority. The vast majority will have the BIOS emulation modes, check your UEFI and disable the CSM setting if you want to ensure it's going to be an EFI boot, otherwise make sure you pick the correct boot entry (usually denoted with "[UEFI] stick vendor name" or similar).

pgoetz

Member

From: Austin, Texas

Registered: 2014-02-21

Posts: 355

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

I will check again, but I could not find any BIOS emulation modes or anything like that in the firmware. I agree with you that this is the norm, particular for rackmount servers, which tend to have conservative configurations. Do you know what mechanism informs the ISO on boot which boot menu to display? I suppose I should read through the archiso wiki entry; will do that later today.

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 12,772

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

What motherboard is used in the server ?

If unsure, the model of the server may help also.

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

clean chroot building not flexible enough ?
Try clean chroot manager by graysky

pgoetz

Member

From: Austin, Texas

Registered: 2014-02-21

Posts: 355

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

What motherboard is used in the server ?

It's Supermicro, OEMed via Thinkmate. It occurred to me that it might be worth looking for a firmware update before trying the install again, but in any case I want to understand how the bootloader decides what
menu to present when booting the Arch ISO. I've had ISO boot issues on a number of (new) high end server systems, at this point, and even though we (currently) use Ubuntu at work, I always use Arch for troubleshooting. Prior to this year I could use the Arch ISO to boot a toaster, in necessary (i.e. if something could boot, Arch would run on it), which is why it's still my last resort when nothing else works.  Things seemed to go a bit wonky when the speech version was added. When a new Arch ISO won't boot a machine, I grab an ISO from 2023 and it just works every time. Not practical for installs, though.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 22,844

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

The bootloader of your UEFI should present you two entries, one is for the BIOS boot and the other for the EFI boot.

pgoetz

Member

From: Austin, Texas

Registered: 2014-02-21

Posts: 355

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

The bootloader of your UEFI should present you two entries, one is for the BIOS boot and the other for the EFI boot.

I'll be back onsite tomorrow and will check it then (again).  I'm going to try to update the firmware first.

pgoetz

Member

From: Austin, Texas

Registered: 2014-02-21

Posts: 355

Re: SOLVED: Boot from 2024-09-01 ISO, get legacy boot on EFI-only system

I updated the system firmware, and now the 2024-09-01 ISO USB shows up as 2 separate entries in the one time boot menu:  one under UEFI and another without that designation (indicating legacy).  Maybe this is just me being an idiot and not noticing the UEFI entry previously, but I did go through this exercise a number of times.  In any case, this solved the problem and the system has successfully been re-installed with up to date Arch.  Closing this as resolved, and thanks for everyone's help/suggestions. I don't understand how the usb can show up as 2 separate boot entries, so this is something to investigate.