Questions tagged [uefi]
Questions about the Unified Extensible Firmware Interface (UEFI), the software interface aiming to replace typical BIOSes. This tag may also be used for questions related to UEFI partitions and systems.
1,053
questions
108
votes
15
answers
731k
views
GRUB starts in command line after reboot
I installed Linux Mint on my laptop along with a pre-installed Windows 10. When I turn on the computer, the normal GRUB menu appears most of the time:
But after booting either Linux or Windows then ...
62
votes
2
answers
71k
views
How to know if I'm booting using UEFI?
I was searching, but didn't find an obvious way to know if GRUB is using UEFI in the system boot, or the BIOS compatibility mode, or a full fledged BIOS. I found only Windows methods. Is there ...
54
votes
8
answers
243k
views
"EFI variables are not supported on this system"
I am attempting to install Arch linux to a new (and very crappy) HP Pavillion 15 Notebook.
This is a UEFI-based machine. After several swings at it, I have managed to get pretty far. Legacy mode is ...
40
votes
5
answers
137k
views
How to boot EFI kernel using QEMU (kvm)?
I'm trying to emulate a EFI environment using QEMU (kmv); virtualbox takes 15 minutes to boot in EFI mode using archboot.
Using legacy BIOS mode, I can boot using this command:
root@citsnmaiko-deb:/...
40
votes
7
answers
10k
views
Why do most distributions chain UEFI and grub?
Most distributions install a additional boot loader on an UEFI system. UEFI
itself is a boot loader, it offers a menu to select different operating
systems or individual kernels. Furthermore, the UEFI ...
39
votes
8
answers
160k
views
Why is USB not working in Linux when it works in UEFI/BIOS?
For background I have just built a new machine with modern hardware including:
AMD FX-8350
Gigabyte GA-990FXA-UD3 motherboard
16GB RAM
NVidia GTX 650 Ti
Kingston SSD
Given that, I tried to install ...
37
votes
1
answer
62k
views
"EFI\boot\bootx64.efi" vs "EFI\ubuntu\grubx64.efi" vs "/boot/grub/x86_64-efi/grub.efi" vs "C:\Windows\Boot\EFI\*"
I have installed Ubuntu 19 64bit alongside Windows 10 64bit and I found that I have 3 different EFI files in different locations:
EFI\boot\bootx64.efi
EFI\ubuntu\grubx64.efi
/boot/grub/x86_64-efi/...
35
votes
1
answer
54k
views
Can GRUB2 share the EFI system partition with Windows?
I have an existing Windows 7 GPT installation, which already has a EFI System partition.
I am now trying to install a Linux on a separate harddisk, which is also GPT formatted. I did not find any ...
30
votes
2
answers
22k
views
When do I need to specify add_efi_memmap as kernel argument in UEFI/EFI boot?
I am reading some tutorials how to EFI stub (efistub) load the Linux kernel. These instructions often use kernel boot parameter add_efi_memmap. The intended hardware is Intel x64 having 8GB of RAM. My ...
24
votes
3
answers
71k
views
VirtualBox: Guest suddenly boots only into UEFI Interactive Shell
Problem with VirtualBox 5.x running on GNU/Linux Debian 9.x host:
EFI-enabled guest suddenly boots only into UEFI Interactive Shell.
It waits for 5 seconds and then it drops to Shell>.
I don't ...
22
votes
1
answer
24k
views
UEFI + BIOS bootable live Debian stretch/buster/bullseye amd64 with persistence
All of the information I currently find on this matter is insufficient for my taste. It is either outdated, misleading or even wrong, seems overly complicated or not covering this specific question.
...
19
votes
1
answer
34k
views
Dual boot windows on second harddrive, UEFI/GPT system
I'd like to install linux, but I don't want to risk damaging my current windows installation as I have heard a lot of horror stories. Fortunately, I have an extra hard drive. Can I install linux ...
18
votes
3
answers
9k
views
Is there a free (libre) open source alternative to memtest86+ that works with UEFI?
In light of memtest86+ not working with UEFI, is there an open source alternative or something I can use from grub to test memory?
17
votes
1
answer
66k
views
Timed out waiting for device dev-disk-by\x2duuid-C829\x2dC4C1.device
I had formatted efi partition and installed windows again. I have dual boot Windows and Linux, then I installed the grub bootloader again from a live usb using these commands:
mount /dev/sda* /mnt
...
17
votes
2
answers
2k
views
The UEFI & SecureBoot impact, how severe?
I'm planning to buy a new laptop in the coming days, and I'm quite impressed with new, cool Ultrabooks. As a long-time GNU/Linux user, I'll of course install a distro of my choice on it.
Chances are ...
16
votes
3
answers
51k
views
Grub installation failed
I had a good running installation of Debian Jessie, but then I ran apt-get update && apt-get upgrade && apt-get dist-upgrade.
And then after rebooting, it came directly to the BIOS. I ...
16
votes
2
answers
33k
views
Is it possible to use Grub to run an EFI binary?
On an efi system it it possible to run arbitrary efi binaries.
Especially I can use the efi shell (one efi binary) to run grub (another efi binary).
Is it also possible to use grub to run for ...
16
votes
2
answers
44k
views
How to clean up bootloaders & UEFI entries from other installs?
I got a new Windows laptop, and I wanted to dual boot with Linux. I installed Fedora, before changing my mind and going back to Mint. I'd like to keep Win 8.1 and Mint.
However, now my UEFI boot menu ...
16
votes
2
answers
4k
views
How do I use the TPM to seal away data on an UEFI booted system?
I would like to seal away files on my system using keys stored in the TPM.
Since my system uses UEFI to boot, I can no longer use TrustedGrub as a boot loader to maintain my trust chain.
Are there any ...
15
votes
4
answers
113k
views
How to repair CentOS ? Failed to mount /sysroot
I have installed centOS 7 on my machine and I am using it for last 4-5 month it was working fine. But few days back due to power cut (un-proper shut down) there is something bad happened with my ...
15
votes
1
answer
15k
views
How do multiple boot loaders work on an EFI system partition
My ESP looks like this
Boot Dell fedora Microsoft
In the Boot directory, their is a boot-loader named bootx64.efi which I understand is the default boot loader that get started first. But in the ...
14
votes
1
answer
76k
views
How to create bootable flash for "efi-shell"
Current Intel server chipsets include a built-in "efi-shell" which appears to basically be a simplified 'NIX with a command set suitable for manipulating some nifty UEFI boot options.
It is also the ...
13
votes
8
answers
56k
views
grub2-install Error: modinfo.sh Missing - Common solutions attempted
I know this is a pretty common problem, but I've tried a bunch of common answers (enumerated below) to no avail.
Basic setup: I'm setting up a Fedora 31 / Ubuntu 18.04 dual-boot, each with a ...
13
votes
4
answers
73k
views
USB booting to installing Linux on a new Lenovo laptop
I recently got a Thinkpad T440s with Windows 8.1 for my job, and since most of my work is done under Linux I am going to install Ubuntu on it, so that I can dual boot. The problem is that it won't ...
13
votes
3
answers
48k
views
Installing linux on an 32bit UEFI only machine
I have a Intel BayTrial Z3735D tablet which comes with a 32bit UEFI BIOS.
After some search I've found that most linux distro don't come with a 32bit efi file.
How can I insert one (or build a new ...
13
votes
2
answers
27k
views
How to recreate EFI boot partition?
I've installed Fedora on my machine with / partition, swap partition and ESP partition for EFI booting.
Now, I was installing Elementary OS instead of Fedora.
I have formatted the / partition (/dev/...
13
votes
1
answer
13k
views
How does grub2 find its configuration file in EFI boot?
There are bazillions of grub2/EFI threads on the net, but I found it difficult to find out how grub2 finds its configuration file in EFI boot. We have been told that in grub2 the configuration file is ...
13
votes
1
answer
10k
views
Installing FreeBSD alongside Linux
I am using Arch Linux with GNOME, I want to install FreeBSD alongside Arch Linux with the following requirements :
I want to keep the Linux GRUB and add an entry of FreeBSD to it.
I want to use ...
12
votes
2
answers
4k
views
Backup my EFI boot entry for easy restore
Giving that Windows 10 would most likely wipe my Linux EFI boot entry, See the comment after the answer here:
Windows 10 will usually "self-heal" its firmware boot entry if you manage to ...
12
votes
1
answer
22k
views
What is the relation between UEFI and Grub?
I installed win10 and a Linux for dual boot on the same ssd, during the installation of Linux, it contains a grub. After installation, I can see there is a new Linux efi file added to the ESP ...
11
votes
3
answers
11k
views
virtualbox uefi PXEBoot
I have successfully managed to setup PXEboot environment (based on foreman) with BIOS based systems. I could do the same with virtualbox using default BIOS subsystem.
As UEFI starts to be more and ...
11
votes
1
answer
19k
views
Unable to shutdown Windows after installing GRUB
I've a Asus ROG laptop that came with Windows 8.1 preinstalled, I upgraded it to Windows 10 and then I wanted to install Bunsenlabs Linux as dual boot. The laptop was UEFI locked and it took me some ...
11
votes
3
answers
37k
views
arch Linux boots into grub command line
I'm trying to install Arch Linux over virtual box guest machine in a UEFI mode.
I've followed beginner's guide to install base system, generate fstab and etc and my system now boots into grub command ...
11
votes
1
answer
14k
views
EFI partition vs /boot partition
I am having trouble understanding the difference between the EFI System Partition (ESP) and the linux /boot partition.
Reading online tells me that /boot partition is going to contain the boot ...
11
votes
2
answers
18k
views
Can I install grub2 on a flash drive to boot both BIOS and UEFI
Well, obviously I can, because all of the Linux distros are delivered as hybrid ISOs that can boot both BIOS and UEFI.
The question is how? I had thought I could run grub-install twice:
grub-install ...
10
votes
1
answer
36k
views
How to manually boot Arch Linux from preboot emergency shell?
I broke an Arch Linux installation. Let's say I made a typo in the PARTUUID string. The result is that the boot process can't mount the root file system and stops at the mkinitcpio preboot stage with ...
10
votes
4
answers
33k
views
Pop OS: systemd-boot can't detect Windows
I've followed the classic procedure to install Windows and Linux in dual boot. First I installed Windows in UEFI mode, then I use a bootable PopOS key to resize the main Windows partition; I created a ...
10
votes
4
answers
8k
views
What should I do before dual-booting Windows 7 and Debian on EFI?
I'm about to purchase an Asus motherboard with EFI firmware and wanted to prepare myself for installing Windows and Debian once the hardware arrives. I was hoping that someone who has gone down this ...
10
votes
2
answers
19k
views
RAID 1 of /boot/efi partition on Debian
I have a CentOS 8 installation, where the partitioning and RAID 1 configuration where done using the automatic partitioning of the CentOS installer. Here is the output of lsblk:
sda 8:0 0 ...
10
votes
2
answers
7k
views
Mirroring EFI System Partition (ESP) on Ubuntu
When setting up a RAID-1 Ubuntu system (i.e. where / and /boot are on RAID-1 mirrors) it's unclear to me what Ubuntu's answer is to making the EFI System Partition (ESP, i.e. /boot/efi) redundant, as ...
10
votes
1
answer
43k
views
How much speed difference for a tweaked bios versus uefi boot? [closed]
EFI can be faster, but that's not certain. The biggest speed
difference is in hardware initialization early in the process. On my
systems, this is a fraction of the total boot time, so a reduction ...
10
votes
2
answers
28k
views
How to move EFI and boot partitions?
I am in the midst of moving these two partitions from sda5 and sda6 to sda1 and sda2 respectively. This is to allow me to have a contiguous space for the root file system to grow. The following is ...
9
votes
6
answers
8k
views
Unmount /boot after booting
For some highly secure bastion VMs I'll implement soon, I am considering to unmount /boot after booting - among other measures of course. Will be mounted only for updating kernel.
Testing this, no ...
9
votes
2
answers
7k
views
Why does the kernel lockdown prevent hibernation?
In my systemd jounal (journalctl) I often see this message:
hibernation is restricted; see man kernel_lockdown.7
This seems to stem from the kernel lockdown feature that (only?) is active when you ...
9
votes
3
answers
21k
views
Boot iso file through uEFI by calling EFI executable inside the iso
I want to create a USB stick that I can use to boot multiple iso files. I want to do this through uEFI.
The usb stick would look something like this:
/EFI
/bootx64.efi
/something.conf
/isos
/...
9
votes
4
answers
3k
views
Determine what program is in my MBR code
I've done a lot of partitioning / dual booting on my Macbook Pro. Right now I have Mac OS X installed along with Ubuntu 12.04, with Grub installed on the Ubuntu partition.
I am wondering - what is ...
9
votes
2
answers
35k
views
Installing Debian: Force UEFI, what does it affect?
I've got a laptop here that came with a Windows 8 installation. What I did: Removed the harddisk, put in an SSD, and now I've (unsuccessfully) tried to install Debian. I've used all the default ...
9
votes
3
answers
13k
views
How to write/edit/update the OsIndications efi variable from command line?
In the need to enter the UEFI firmware setup utility while using ultra fast boot (keyboard drivers are not loaded during POST), I wish to write to the "Os Indications" efi variable. My OS is Ubuntu 14....
9
votes
1
answer
14k
views
What is the proper way to use ISOLINUX with UEFI?
I've been trying to add UEFI support in the 64-bit version of Minimal Linux Live for quite some time, unfortunately without much success. As you can see from the below image, I get critical error each ...
8
votes
3
answers
31k
views
(UEFI) Chainloading GRUB from GRUB
Terminology: ESP = my FAT32 EFI partition.
I want to:
Have a self-contained GRUB install on my ESP that chainloads another GRUB bootloader on my distro root filesystem (/). I currently have several ...