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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.

50
votes
2answers
49k 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 ...
31
votes
8answers
117k 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 ...
30
votes
1answer
40k 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
7answers
5k 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 ...
28
votes
2answers
10k 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 ...
21
votes
4answers
61k 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:/...
18
votes
2answers
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 ...
17
votes
8answers
101k 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 ...
17
votes
1answer
16k views

UEFI + BIOS bootable live Debian stretch 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. ...
17
votes
5answers
68k 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 ...
15
votes
1answer
24k 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 ...
14
votes
2answers
2k 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 ...
13
votes
1answer
8k 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 ...
13
votes
1answer
65k 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 ...
11
votes
3answers
39k 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 ...
11
votes
1answer
6k 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 ...
10
votes
2answers
16k 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 ...
10
votes
4answers
59k 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 ...
10
votes
4answers
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 ...
9
votes
3answers
7k 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....
8
votes
2answers
14k 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/...
8
votes
1answer
2k views

Booting EFI on KVM

I'm on Ubuntu 14.04 running kernel 3.19. I'm trying to use virt-manager to start a virtual machine. I have installed ovmf for EFI firmware and booted the machine with a Gentoo ISO in the CD slot. I ...
8
votes
3answers
4k views

Is there a way to enable secure boot in Linux?

Just like Windows has secure boot that prevents any external OS Loader code from running at boot, does Linux have any similar option for itself? I have looked around, but when I search, the only ...
7
votes
3answers
12k 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 ...
7
votes
1answer
33k 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 ...
7
votes
2answers
392 views

Is there a command or method (other than RTFM) to determine if a system has a UEFI BIOS?

My inspiration for asking this is this other question on Ask Ubuntu. One reason I am asking is that I am just curious. I would like to know more about this for whatever value it might have in the ...
7
votes
2answers
2k views

Can't boot, task btrfs-transacti blocked for more than 120 seconds, how to fix this?

My computer was set up to boot Ubuntu 15.04 via UEFI. I have two disks. My first disk /dev/sda is a 128 GB ssd formatted as GPT, containing an EFI partition and a btrfs partiton with subvolume @ ...
7
votes
5answers
18k views

How to build a live Debian CD/USB in Windows, bootable in EFI mode?

I tried to install the latest stable Debian release (Debian 7.0 "Wheezy") using the Debian Multi-arch netinstall (AMD64) "debian-7.0.0-amd64-i386-netinst.iso" on my laptop. My laptop has a SecureCore ...
7
votes
1answer
10k views

UEFI install (14.04) boots to GRUB command prompt, no GUI

I just installed zorin 9 core (14.04) on my Hard-Disk in UEFI mode. But, when I boot, all that comes up is a GRUB2 command line. I've searched for solution and came up with this command configfile (...
7
votes
2answers
1k 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 ...
6
votes
4answers
32k 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 ...
6
votes
6answers
37k views

Restore EFI boot partition

I am triple booting Ubuntu, Debian, and Fedora. When I installed Fedora from a liveCD I got excited and kept hitting next, not realizing I was not installing GPT, but rather LVM. After doing this I ...
6
votes
2answers
3k views

How to construct a GPT-only partition table on Linux?

All of the tools I've tried until now were only capable to create a dual (GPT & MBR) partition table, where the first 4 of the GPT partitions were mirrored to a compatible MBR partition. This is ...
6
votes
3answers
15k 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 ...
6
votes
2answers
4k views

Partitioning for dual boot of two Linux systems

I would like to have dual boot of two Linux distributions on my laptop. One stable (Mint 18 that I found to work well with Yoga 3 Pro) and one that would be probably changing often; I want to try ...
6
votes
1answer
6k 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 an answer to the question above. We have been told that in grub2 the configuration file is /boot/grub/grub.cfg. ...
6
votes
3answers
6k views

Partitioning EFI machine with two SSD disks in mirror

I have two SSD disks, I want to put them in a software mirror RAID. But whatever I do the OpenSuSe installation keeps telling me that due to the partitioning scheme he won't be able to install the ...
6
votes
1answer
5k views

UEFI and Puppy Linux

I recently installed Puppy Linux on a USB stick using the Universal USB Installer, but I have not being able to boot from it. My notebook came with Windows 8 and had the secure boot activated at UEFI. ...
6
votes
1answer
1k views

Boot FreeBSD in legacy mode on GPT disk

I am trying to install FreeBSD in legacy mode (BIOS) on a UEFI system, since I have an Intel Iris Graphics 6100, which is from Broadwell series and is not supported yet by the intel driver, so I want ...
6
votes
2answers
22k 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 ...
6
votes
4answers
2k views

Two EFI disks with Grub2

I bought two SSD disks and as usual I though that installing Windows on a completely separate disk would be the easiest solution, but I can't find any tutorials for dual booting with grub2 (efi). All ...
6
votes
1answer
2k views

EFI boot to Linux on a MacBook Pro

8,3 MacBook Pro 2011, running Ubuntu 11.10 amd64. Here's the situation. Screen backlight and a few other things only work if booting in EFI, so I need to boot Ubuntu in EFI to get things working. ...
6
votes
3answers
7k views

How to make UEFI bootable usb disk from bios bootable iso

Suppose you have an iso image that contains a bios bootable partition. You can write this image to a usb disk In linux you could do this for example with dd if=pmagic_2013_02_28.iso of/dev/sdc1 ...
5
votes
3answers
2k views

GPU passthrough works with UEFI firmware but not Windows iso

I am trying to set up a virtual machine with passthrough graphics. I am able to get the passthrough working for the UEFI shell, but not the official Windows installer. I can get the Windows installer ...
5
votes
1answer
1k views

Does using UEFI increase battery life?

I've heard about a better power management when using UEFI instead of BIOS. Is that true? It was about energy consumption being more efficient or something like that. If it is true, has the ...
5
votes
2answers
12k 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 ...
5
votes
1answer
7k views

32bit EFI with 64 bit linux OS. Can it be done?

I have a 32bit ubuntu linux install on an hp stream 7 tablet. For the sake of long term support I would like to install 64bit ubuntu linux on this device. The tablet has a 64 bit intel baytrail ...
5
votes
1answer
33k views

Creating EFI bootable GPT partition with gdisk on previous MBR, GPT Damaged

So this is a sister question to my previous one about partitioning for a UEFI boot loader. Parititioning for a UEFI boot loader, can LVM be used? Disclaimer: I don't give a flip about the data on it....
5
votes
1answer
4k 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 ...
5
votes
2answers
9k 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 ...