"EFI variables are not supported on this system." Despite using UEFI

Issues & Assistance
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1

Hello. Hope y’all are having a good day.

My issue is exactly what the title says. I get that exact output after running efibootmgr -v despite setting UEFI everywhere.

Bios is in UEFI. My drives and partitions are in GPT. Running cat /sys/firmware/efi/fw_platform_size returns 64. I’ve tried most of the potential fixes that I see mentioned on various forums. I’ve tried reformatting my USB multiple times both with Ventoy and Rufus all of which setting GPT and UEFI.

I’ve installed other Ubuntu Distros in UEFI and i’ve only had this issue with CachyOS/Arch. (I do have an issue with not being able to install any fedora based distros that could be caused by this same issue, but that’s another story.).

I’ve tried Grub, systemd, rEFInd, all of which did not work. I’ve set my FAT32 boot partition to 4GB though during installation it seems like nothing is getting written there anyway (storage size does not change.).

Long story short I’ve tried my best to search around for solutions and have gotten nowhere. Attempting to install Cachyos only throws out the The bootloader could not be installed. The installation command <pre>grub-install--target-x86_64-efi --efi- directory=/boot/efi -bootloader-id=cachyos-force</pre> returned error code 1. error.

I am completely lost as to what else i can do. Any help is appreciated.
Bear with me as I’m very new to linux as a whole, apologies if i require spoon-feeding in certain areas.

2

The most basic information is missing.
What is your motherboard make/version ?
Is this a laptop or desktop?

Its possible you have a BIOS that does not fully implement UEFI standards and you will need to keep the motherboard in BIOS mode.

When you installed say Ubuntu or Linux Mint did

efibootmgr

Give you output? You should see a timeout, boot stanzas and order similar to:

BootCurrent: 0005
Timeout: 0 seconds
BootOrder: 0005,0001,0000,2001,2002,2003
Boot0000* HDD0: Micron_2450_MTFDKBA512TFK PciRoot(0x0)/Pci(0xe,0x0)/NVMe(0x1,00-A0-75-01-45-A6-F2-78)/HD(13,GPT,059352b9-797c-459f-9814-2a5477be6e7a,0x3b5df000,0x200000)RC
Boot0001* Windows Boot Manager HD(1,GPT,d9e3661c-4a66-4994-a090-3a9094720e88,0x800,0x82000)/\EFI\Microsoft\Boot\bootmgfw.efi57494e444f5753000100000088000000780000004200430044004f0042004a004500430054003d007b00390064006500610038003600320063002d0035006300640064002d0034006500370030002d0061006300630031002d006600330032006200330034003400640034003700390035007d00000030000100000010000000040000007fff0400
Boot0005* ubuntu HD(1,GPT,d9e3661c-4a66-4994-a090-3a9094720e88,0x800,0x82000)/\EFI\ubuntu\shimx64.efi

Post the motherboard, make model and current BIOS version you are using

3

Hello. Thank you for responding.

Motherboard is an MSI B650M-A WIFI. i did not run efibootmgr on other Ubuntu based distros because i never had the issue to begin with, though i can run a live session later and come back to you with the output.

4

After running efibootmgr in Kubuntu (another distro that worked for me awhile back) it surprisingly came back with the same error. I had no issue installing it in the past alongside Mint so this is a bit of a surprise to me. All my drives are in GPT.

For more additional info here is my log file from previous failed attempts at installing cachyos: https://termbin.com/qa8e

My motherboard is on bios version E7D77AMS.1P1 build date 04/29/2025.
Secure boot/TPM are all off.

5

Have you got windows on that machine ?

That motherboard does not implement a full UEFI BIOS so install using BIOS mode.
This may not be the linux distribution for you as it is advanced and based on Arch Linux.
Luckily the CachyOS installer does a lot of the work, but you need to be familiar with the linux shell, terminal commands, filesystems, and grub. Without these basic skills, it will not be psossible for you to install. You can seek out Linux User Groups, LUG if there are any in your area.

Installation.
Set your motherboard for BIOS, possibly done this.
Boot from a live USB install of CachyOS, follow the install instructions for MBR/BIOS, link below:

However I would set the / partition to 40 or 50G as some packages (e.g. arduino, Kicad can install a lot of data under root. Choose any filesystem, btrfs is CachyOS, ext4 is Arch recommended, and
is ultra stable, no fragmentation etc.
When you get to the partitioning screen, link:

https://discuss.cachyos.org/uploads/default/original/2X/7/78eb257567de947545d6b9f69e5fe1af39363b22.png

Choose MANUAL partitioning.
Your disk layout will not be the same. your disk may be identified as either /dev/sda or /dev/sda
But what you do, is delete any existing partitions, create a new partion, example /dev/sda1 set its size to 50G, choose ext4 or btrfs and set its mount point as /
You can then choose the rest of the drive as /home, filesystem as ext4 or btrfs
and follow the steps to create the partions and install CachyOS

Right at the end of the install you may get an error, cannot install grub or no /boot or no UEFI partition exists, (or words to that effect) continue anyway.

You need to know what partition the root filesystem is (possibly /dev/sda1) in your case.
Reboot.
If all goes well you have a working Cachy using BIOS/MBR, scheme.

If the system fails to boot, dont panic.
Boot from the Live USB image of Cachy. Wait until it gets to the KDE desktop.
Open the terminal ctrl-alt-t
Type

fdisk -l

That command should show you the partitions you created. There should be at least 2, / and /home you may have created a /swap partition
The important thing to note is the drive designation, it should report /dev/sda1 for root.

To install grub on that system, keep the terminal open and run

sudo os-prober
sudo grub-install /dev/sda

Thats all you need to do. If you have more that one drive, make sure that sda is the correct drive,
no digit after the drive, you need it to be installed to the MBR.

It may sound complicated, but its quicker to restore than it is for me to type this reply.
An alternative solution is to install another Linux installation e.g. Linux Mint, but make sure that you dont use all the drive space up, say 50G for / and maybe 70G for /home
Then when you install Cachy, choose manual partitioning, you would see a /dev/sda1 and /dev/sda2 for your linux system, you would then use the free space for CachyOS.

Good |Luck.

6

So this is a mistake on my end, after importing default bios settings i am able to get a return for efibootmgr -v and I’ve installed Cachyos. What I’m suspecting is previous bios settings that I’ve experimented with and disabled through SCEWIN are probably related to the UEFI features.

I will be going through my SCEWIN bios settings and diving into which settings are the ones directly related top the UEFI features/which ones are the cause, and when I do I’ll edit this post with my findings.

7

Sorry to waste your time, but the motherboard isn’t at fault (explained in my other post). And if i were able to wipe my disk clean i would’ve done so and have started with a clean slate (i have all my games installed on the same drive alongside a windows dual boot, also with a lot of files).

Either way appreciate you attempting to guide me.