EFI Variables Are Not Supported On This System (Whilst Restoring Grub)

Hi. I am running a system with Windows 10 and Manjaro dual boot on two separate disks. I was booting the disk with Manjaro installed, and GRUB would enable me to select between the two OS'. After reinstalling Windows, GRUB no longer recognized the Windows boot entry, so I went about trying to resolve it. However, it seems that all the commands I find ultimately lead to the following error:

EFI variables are not supported on this system.

I searched and found a thread with the same title (EFI variables are not supported on this system) and they say that this means that I have managed to install Manjaro in legacy mode. They say the solution is to reinstall Linux.
Since I've already been using this config for some time, I just wanted to make sure that this really is my only option to get the GRUB working correctly again, since I've already been using it for a long time, and it worked.

PS.: This was the guide I was using to try to restore GRUB:


If you want to install Windoze and Manjaro as dual boot on the same disk both OS have to be installed in the same mode, i.e. legacy (BIOS) mode with MBR parted disk or UEFI with gpt parted disk.

Even if installed on two disks it is recommendable to have them in the same mode to use Manjaro's grub menu to boot both OS. Otherwise you can switch only via firmware selection of booting disk.

So, if you intend to keep your Manjaro install, re-install Windoze in the same mode with same disk partition scheme.

To save your self from a lot of trouble.

Cisable CSM or Legacay boot and enable only EFI.


Thank you, but I do have Windows and Manjaro installed on two separate disks, and would like to keep them on separate disks.

Thank you for your reply. Do you mean disable CSM or Legacy boot from BIOS? I have an x470 Taichi motherboard with the latest BIOS update. I'm not sure I even saw an option to change boot options. I will double check now though. Are you saying this will fix my current issue without having to reinstall?

What is the status with regard legacy / UEFI for the both OS?

Could you provide output of

inxi -Fxxxza --no-host
sudo fdisk -l
lsblk -f

Looks like both your system are installed in legacy/mbr mode now.
If this is the case , you could try reinstalling Manjaro's grub for legacy mode and not for uefi mode.

To be sure, please post the output of
sudo parted -l
for the forum to have a more detailed info on your disk set-up.

edit: didn't see @Wollie's post before posting :blush:

inxi -Fxxxza --no-host
System:    Kernel: 4.19.102-1-MANJARO x86_64 bits: 64 compiler: gcc v: 9.2.0 
           parameters: BOOT_IMAGE=/boot/vmlinuz-4.19-x86_64 root=UUID=16fefc4b-fbca-45a6-86b9-229e4ab49333 rw loglevel=3 quiet 
           Desktop: KDE Plasma 5.17.5 tk: Qt 5.14.1 wm: kwin_x11 dm: SDDM Distro: Manjaro Linux 
Machine:   Type: Desktop Mobo: ASRock model: X470 Taichi serial: <filter> UEFI [Legacy]: American Megatrends v: P3.90 
           date: 01/10/2020 
CPU:       Topology: 12-Core model: AMD Ryzen 9 3900X bits: 64 type: MT MCP arch: Zen family: 17 (23) model-id: 71 (113) 
           stepping: N/A microcode: 8701013 L2 cache: 6144 KiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm bogomips: 182409 
           Speed: 2213 MHz min/max: 2200/3800 MHz boost: enabled Core speeds (MHz): 1: 2203 2: 2202 3: 2208 4: 2201 5: 2202 
           6: 2200 7: 2201 8: 2200 9: 2191 10: 2202 11: 2188 12: 2207 13: 2200 14: 2199 15: 2192 16: 2198 17: 2188 18: 2200 
           19: 2209 20: 2200 21: 2200 22: 2200 23: 2200 24: 2202 
           Vulnerabilities: Type: itlb_multihit status: Not affected 
           Type: l1tf status: Not affected 
           Type: mds status: Not affected 
           Type: meltdown status: Not affected 
           Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via prctl and seccomp 
           Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer sanitization 
           Type: spectre_v2 mitigation: Full AMD retpoline, IBPB: conditional, STIBP: conditional, RSB filling 
           Type: tsx_async_abort status: Not affected 
Graphics:  Device-1: NVIDIA TU116 [GeForce GTX 1660] vendor: ZOTAC driver: nvidia v: 430.64 bus ID: 0e:00.0 chip ID: 10de:2184 
           Display: x11 server: X.Org 1.20.7 driver: nvidia unloaded: modesetting,nouveau alternate: fbdev,nv,vesa 
           compositor: kwin_x11 resolution: 1920x1080~60Hz, 3840x2160~60Hz 
           OpenGL: renderer: GeForce GTX 1660/PCIe/SSE2 v: 4.6.0 NVIDIA 430.64 direct render: Yes 
Audio:     Device-1: NVIDIA vendor: ZOTAC driver: snd_hda_intel v: kernel bus ID: 0e:00.1 chip ID: 10de:1aeb 
           Device-2: Advanced Micro Devices [AMD] Starship/Matisse HD Audio vendor: ASRock driver: snd_hda_intel v: kernel 
           bus ID: 10:00.4 chip ID: 1022:1487 
           Sound Server: ALSA v: k4.19.102-1-MANJARO 
Network:   Device-1: Intel Dual Band Wireless-AC 3168NGW [Stone Peak] driver: iwlwifi v: kernel port: e000 bus ID: 08:00.0 
           chip ID: 8086:24fb 
           IF: wlp8s0 state: up mac: <filter> 
           Device-2: Intel I211 Gigabit Network vendor: ASRock driver: igb v: 5.4.0-k port: d000 bus ID: 0a:00.0 
           chip ID: 8086:1539 
           IF: enp10s0 state: down mac: <filter> 
Drives:    Local Storage: total: 5.46 TiB used: 97.30 GiB (1.7%) 
           ID-1: /dev/nvme0n1 vendor: Samsung model: SSD 970 EVO Plus 500GB size: 465.76 GiB block size: physical: 512 B 
           logical: 512 B speed: 31.6 Gb/s lanes: 4 serial: <filter> rev: 1B2QEXM7 scheme: GPT 
           ID-2: /dev/sda vendor: Crucial model: CT500MX500SSD1 size: 465.76 GiB block size: physical: 4096 B logical: 512 B 
           speed: 6.0 Gb/s serial: <filter> rev: 023 scheme: MBR 
           ID-3: /dev/sdb vendor: Toshiba model: HDWE150 size: 4.55 TiB block size: physical: 4096 B logical: 512 B 
           speed: 6.0 Gb/s rotation: 7200 rpm serial: <filter> rev: FP1R scheme: GPT 
Partition: ID-1: / raw size: 465.76 GiB size: 457.45 GiB (98.22%) used: 97.30 GiB (21.3%) fs: ext4 dev: /dev/sda1 
Sensors:   System Temperatures: cpu: 52.0 C mobo: N/A gpu: nvidia temp: 39 C 
           Fan Speeds (RPM): N/A gpu: nvidia fan: 37% 
Info:      Processes: 392 Uptime: 1m Memory: 62.83 GiB used: 1.51 GiB (2.4%) Init: systemd v: 242 Compilers: gcc: 9.2.0 
           Shell: bash v: 5.0.11 running in: yakuake inxi: 3.0.37 
sudo fdisk -l
Disk /dev/nvme0n1: 465.78 GiB, 500107862016 bytes, 976773168 sectors
Disk model: Samsung SSD 970 EVO Plus 500GB          
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: C01BF92D-C4FB-4D64-9852-A6732A1E5D6E

Device           Start       End   Sectors   Size Type
/dev/nvme0n1p1    2048   1023999   1021952   499M Windows recovery environment
/dev/nvme0n1p2 1024000   1228799    204800   100M EFI System
/dev/nvme0n1p3 1228800   1261567     32768    16M Microsoft reserved
/dev/nvme0n1p4 1261568 976771071 975509504 465.2G Microsoft basic data

Disk /dev/sda: 465.78 GiB, 500107862016 bytes, 976773168 sectors
Disk model: CT500MX500SSD1  
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0xa34a8323

Device     Boot Start       End   Sectors   Size Id Type
/dev/sda1  *     2048 976769023 976766976 465.8G 83 Linux

Disk /dev/sdb: 4.56 TiB, 5000981078016 bytes, 9767541168 sectors
Disk model: TOSHIBA HDWE150 
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: AD566C10-42FA-4F3C-956B-526EEADA4C9B

Device     Start        End    Sectors  Size Type
/dev/sdb1     34      32767      32734   16M Microsoft reserved
/dev/sdb2  32768 9767538687 9767505920  4.6T Microsoft basic data

Partition 1 does not start on physical sector boundary.

Disk /dev/loop0: 181.8 MiB, 189870080 bytes, 370840 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop1: 89.9 MiB, 93417472 bytes, 182456 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop2: 173.35 MiB, 181760000 bytes, 355000 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
lsblk -f
NAME        FSTYPE   FSVER LABEL    UUID                                 FSAVAIL FSUSE% MOUNTPOINT
loop0       squashfs 4.0                                                       0   100% /var/lib/snapd/snap/spotify/36
loop1       squashfs 4.0                                                       0   100% /var/lib/snapd/snap/core/8268
loop2       squashfs 4.0                                                       0   100% /var/lib/snapd/snap/skype/112
└─sda1      ext4     1.0            16fefc4b-fbca-45a6-86b9-229e4ab49333  336.9G    21% /
└─sdb2      ntfs           Storage  48D23114D2310828                                    
├─nvme0n1p1 ntfs           Recovery BA58DC9958DC562B                                    
├─nvme0n1p2 vfat     FAT32          EADE-2695                                           
└─nvme0n1p4 ntfs                    08D8EA32D8EA1E26    

You've got your systems installed in different modes, Windows in UEFI and Manjaro in Legacy/MBR. You could perhaps consider reinstalling Manjaro in UEFI as well.

Okay, thanks for the input. I'm just not sure how this happened. I recently reinstalled Windows and I think it made me change to UEFI, because I remember it saying Windows was not installable on the drive due to it's partitioning. But I'm not sure how it would have had that partitioning in the first place, if it wasn't valid for Windows (I installed Windows myself both times). Perhaps it has to do with the BIOS update I had to make in order to support the Ryzen 9 3900x on the x470 Taichi motherboard.

It is a plausible scenario. I have always installed Windows in UEFI on GPT disk and the installer makes exactly the same partitions as yours.

If you go for reinstalling Manjaro, you might want to backup, apart from your personal data in your home folder, the hidden .files and .folders as they contain your personal settings for your apps, desktop etc. You could then add them one by one as you go (at least this is what I do) in your new install.

If you search the forum there are posts for how to make a list of the packages you have installed to be able to reinstall them in one shot.

To install Manjaro in UEFI, make sure you boot up your usb in the same mode. Once in the live session, launch gparted or kde partition manager to convert your disk to gpt by creating a new partition table.

Okay, thanks for the help (and to others in the thread who took the time to respond). I think I will reinstall and keep in mind to boot the USB as UEFI and use the GPT partition scheme from the installer.


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