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.
Questions tagged [uefi]
1004 questions
102
votes
15 answers
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 rebooting, I GRUB starts in command line mode, as…
Antoine Aubry
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- 2
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61
votes
2 answers
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 something in GRUB or the Kernel boot logs that shows if…
Braiam
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49
votes
8 answers
"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 disabled in the system setup, and I have…
John Dibling
- 2,180
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40
votes
7 answers
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 settings can easily be
altered with userspace…
Marco
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40
votes
5 answers
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:/home/maiko/uefi/ovmf# qemu-system-x86_64 -kernel …
MaikoID
- 969
- 3
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- 18
39
votes
8 answers
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 various versions of Linux on the SSD and was met…
BrionS
- 841
- 1
- 7
- 10
35
votes
1 answer
"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/grub.efi
What are the differences between these…
Yousha Aleayoub
- 738
- 2
- 9
- 21
35
votes
1 answer
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 working way to get grub booting without EFI system…
crater2150
- 3,836
- 2
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30
votes
2 answers
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 current setup is running grub-efi bootloader and…
Pro Backup
- 4,686
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- 82
22
votes
1 answer
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.
Goals:
bootable USB drive (both UEFI and legacy…
schlimmchen
- 1,307
- 2
- 12
- 16
22
votes
3 answers
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 remember any modifications, which I would have done,…
Vlastimil Burián
- 27,586
- 56
- 179
- 309
19
votes
1 answer
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 onto that and then dual boot windows without having…
goldilocks
- 86,451
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- 258
17
votes
2 answers
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 I'll have to buy a computer with Windows 8…
user27225
17
votes
3 answers
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?
Evan Carroll
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16
votes
2 answers
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 alternatives / ways to make use of the TPM on…
Marcus
- 243
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