- Clover Bootable Usb Windows
- Clover Bootable Usb Mojave
- Create Clover Bootable Usb
- Clover Bootable Usb High Sierra
- Clover Bootable Usb Flash Drive
The Unified Extensible Firmware Interface (UEFI or EFI for short) is a new model for the interface between operating systems and firmware. It provides a standard environment for booting an operating system and running pre-boot applications. Mar 19, 2017 Still need bootable USB. When Clover Boot Manager appear go to option and make sure that it don’t inject Nvidia and don’t use Nvidia Web Driver, then select internalhfs ( Boot Mac OS X from. AIO Boot is an All-in-One bootable software for USB and HDD. Is one of the best Multiboot USB Creator for Windows. Clover and install Grub4dos. The Unified Extensible Firmware Interface (UEFI or EFI for short) is a new model for the interface between operating systems and firmware. It provides a standard environment for booting an operating system and running pre-boot applications.
or Win32 Disk Imager, this article will guide you how to create FreeBSD bootable USB from Windows without data loss.What is FreeBSD?
FreeBSD is a free and open-source Unix-like operating system descended from Research Unix via the Berkeley Software Distribution (BSD). Although for legal reasons FreeBSD cannot use the Unix trademark, it is a direct descendant of BSD, which was historically also called “BSD Unix” or “Berkeley Unix”. The first version of FreeBSD was released in 1993, and today FreeBSD is the most widely used open-source BSD distribution, accounting for more than three-quarters of all installed systems running open-source BSD derivatives.
See more at Wikipedia.
Create FreeBSD bootable USB
AIO Boot supports booting all in one USB, including FreeBSD. And with the help of the Partition Image Mapper tool, you can boot many other operating systems. This tool allows you to temporarily use the partition image file as a real partition. The great thing is that FreeBSD also provides a partition image. You can then restore the partition as before without losing data.
This method supports booting FreeBSD in both Legacy and UEFI modes.
For FreeBSD, TrueOS, PC-BSD and FreeBSD-based operating systems, you can easily create a USB installer using the following steps:
- Download and install AIO Boot for USB.
- Download FreeBSD as an image of USB (XYZ-memstick.img).
- Open the file you downloaded above with 7-Zip.
- Extract the 2.ufs file into the /AIO/Files/PartIMG folder on the AIO Boot drive. Depending on the version in which the file name may be different, you need to extract the largest file. You can rename this file for ease of remembering.
- Now you need to copy PartIMGMapper.exe to another drive. Because this application does not allow to run on the destination drive.
- Run PartIMGMapper.exe:
- Select /AIO/Files/PartIMG/PartIMG_ROOT.img in row 1. Because we will use Grub2 to boot into FreeBSD.
- Select the /AIO/Files/PartIMG/2.ufs that you extracted above in row 2.
- Click MAP button.
- The tool will back up the partition table information for later restoration. The file has .MBR extension in the same directory as PartIMGMapper.exe.
- Once used, run PartIMGMapper.exe, click UNMAP and select the previously backed up MBR file. All data and partitions will be restored as before.
- Boot into USB, then boot FreeBSD from the PartIMG Partition menu (press the k key for quick access).
PartIMG Mapper
PartIMG Mapper has the same features as Partition Image Mapper, but it runs directly on Grub2 and Grub4dos without Windows.
FreeBSD do not allow overlapping partitions. This means that the beginning of this partition is part of another partition. To fix this, just delete the partition where you are putting the 2.ufs file above.
- Access the PartIMA Mapper menu, then MAP the PartIMG_ROOT.img and 2.ufs files. You will now have two new partitions.
- Access the Change root partition menu, then select the PARTIMGROOT partition as the root partition. Then access the Partition Tools menu and Backup MBR.
- Access the Change root partition menu, then select the PARTIMGROOT partition as the root partition. Then access the Partition Tools menu, select the AIOBOOT partition where you placed the two files, and then select Delete to delete the partition.
- You can now boot FreeBSD from the PartIMG Partition menu.
- Once you have installed FreeBSD, you can restore the deleted partition. Access the Partition Tools menu and select Restore MBR. Now from the AIO Boot partition, delete the two new partitions that you have MAP in step 1.
Good luck!
Warning:This article or section is out of date.
The Unified Extensible Firmware Interface (UEFI or EFI for short) is a new model for the interface between operating systems and firmware. It provides a standard environment for booting an operating system and running pre-boot applications.
It is distinct from the commonly used 'MBR boot code' method followed for BIOS systems. See Arch boot process for their differences and the boot process using UEFI. To set up UEFI boot loaders, see Arch boot process#Boot loader.
UEFI versions
- UEFI started as Intel's EFI in versions 1.x.
- Later, a group of companies called the UEFI Forum took over its development, which renamed it as Unified EFI starting with version 2.0.
- Unless specified as EFI 1.x, EFI and UEFI terms are used interchangeably to denote UEFI 2.x firmware.
- Apple's EFI implementation is neither a EFI 1.x version nor UEFI 2.x version but mixes up both. This kind of firmware does not fall under any one (U)EFI specification and therefore is not a standard UEFI firmware. Unless stated explicitly, these instructions are general and some of them may not work or may be different in Apple Macs.
The latest UEFI specification can be found at https://uefi.org/specifications.
UEFI firmware bitness
Under UEFI, every program whether it is an OS loader or a utility (e.g. a memory testing app or recovery tool), should be a EFI application corresponding to the UEFI firmware bitness/architecture.
The vast majority of UEFI firmwares, including recent Apple Macs, use x86_64 UEFI firmware. The only known devices that use IA32 (32-bit) UEFI are older (pre 2008) Apple Macs, Intel Atom System-on-Chip systems (as on 2 November 2013)[1] and some older Intel server boards that are known to operate on Intel EFI 1.10 firmware.
An x86_64 UEFI firmware does not include support for launching 32-bit EFI applications (unlike x86_64 Linux and Windows versions which include such support). Therefore the EFI application must be compiled for that specific firmware processor bitness/architecture.
i386-efi
target.Checking the firmware bitness
The firmware bitness can be checked from a booted operating system.
From Linux
On distributions running Linux kernel 4.0 or newer, the UEFI firmware bitness can be found via the sysfs interface. Run:
It will return 64
for a 64-bit (x86_64) UEFI or 32
for a 32-bit (IA32) UEFI. If the file does not exist, then you have not booted in UEFI mode.
From macOS
Pre-2008 Macs mostly have IA32 EFI firmware while >=2008 Macs have mostly x86_64 EFI. All Macs capable of running Mac OS X Snow Leopard 64-bit Kernel have x86_64 EFI 1.x firmware.
To find out the arch of the EFI firmware in a Mac, type the following into the Mac OS X terminal:
If the command returns EFI32
then it is IA32 (32-bit) EFI firmware. If it returns EFI64
then it is x86_64 EFI firmware. Most of the Macs do not have UEFI 2.x firmware as Apple's EFI implementation is not fully compliant with UEFI 2.x specification.
From Microsoft Windows
64-bit versions of Windows do not support booting on a 32-bit UEFI. So, if you have a 32-bit version of Windows booted in UEFI mode, you have a 32-bit UEFI.
To check the bitness run msinfo32.exe
. In the System Summary section look at the values of 'System Type' and 'BIOS mode'.
For a 64-bit Windows on a 64-bit UEFI it will be System Type: x64-based PC
and BIOS mode: UEFI
, for a 32-bit Windows on a 32-bit UEFI - System Type: x86-based PC
and BIOS mode: UEFI
. If the 'BIOS mode' is not UEFI
, then Windows is not booted in UEFI mode.
Linux kernel config options for UEFI
The required Linux Kernel configuration options[2] for UEFI systems are:
UEFI Runtime Variables Support (efivarfs filesystem - /sys/firmware/efi/efivars
). This option is important as this is required to manipulate UEFI runtime variables using tools like /usr/bin/efibootmgr
. The below config option has been added in kernel 3.10 and above.
UEFI Runtime Variables Support (old efivars sysfs interface - /sys/firmware/efi/vars
). This option should be disabled to prevent any potential issues with both efivarfs and sysfs-efivars enabled.
GUID Partition Table (GPT) config option - mandatory for UEFI support
EFI mixed-mode support - to boot a x64_64 kernel on a IA32 UEFI.
UEFI variables
UEFI defines variables through which an operating system can interact with the firmware. UEFI boot variables are used by the boot loader and used by the OS only for early system start-up. UEFI runtime variables allow an OS to manage certain settings of the firmware like the UEFI boot manager or managing the keys for UEFI Secure Boot protocol etc. You can get the list using:
UEFI variables support in Linux kernel
Linux kernel exposes UEFI variables data to userspace via efivarfs (EFIVARiable FileSystem) interface (CONFIG_EFIVAR_FS
) - mounted using efivarfs
kernel module at /sys/firmware/efi/efivars
- it has no maximum per-variable size limitation and supports UEFI Secure Boot variables. Introduced in kernel 3.8.
Requirements for UEFI variable support
- Kernel should be booted in UEFI mode via EFISTUB (optionally using a boot manager) or by a UEFI boot loader, not via BIOS or CSM, or Apple's Boot Camp which is also a CSM.
- EFI Runtime Services support should be present in the kernel (
CONFIG_EFI=y
, check if present withzgrep CONFIG_EFI /proc/config.gz
). - EFI Runtime Services in the kernel SHOULD NOT be disabled via kernel cmdline, i.e.
noefi
kernel parameter SHOULD NOT be used. efivarfs
filesystem should be mounted at/sys/firmware/efi/efivars
, otherwise follow #Mount efivarfs section below.efivar
should list (option-l
/--list
) the UEFI variables without any error.
If UEFI Variables support does not work even after the above conditions are satisfied, try the below workarounds:
- If listing of the UEFI variables (
efivar -l
) leads toefivar: error listing variables: Function not implemented
and the system is booted into a realtime kernel, addefi=runtime
to the kernel parameters and reboot (efivarfs functionality is disabled by default on those kernels). - If any userspace tool is unable to modify UEFI variable data, check for existence of
/sys/firmware/efi/efivars/dump-*
files. If they exist, delete them, reboot and retry again. - If the above step does not fix the issue, try booting with
efi_no_storage_paranoia
kernel parameter to disable kernel UEFI variable storage space check that may prevent writing/modification of UEFI variables.
efi_no_storage_paranoia
should only be used when needed and should not be left as a normal boot option. The effect of this kernel command line parameter turns off a safeguard that was put in place to help avoid the bricking of machines when the NVRAM gets too full. See FS#34641 for more information.Mount efivarfs
If efivarfs
is not automatically mounted at /sys/firmware/efi/efivars
by systemd during boot, then you need to manually mount it to expose UEFI variables to userspace tools like efibootmgr:
See efivarfs.html for kernel documentation.
Userspace tools
There are few tools that can access/modify the UEFI variables, namely
- efivar — Library and Tool to manipulate UEFI variables (used by efibootmgr)
- https://github.com/rhboot/efivar || efivar, efivar-gitAUR
- efibootmgr — Tool to manipulate UEFI Firmware Boot Manager Settings
- https://github.com/rhboot/efibootmgr || efibootmgr
- uefivars — Dumps list of UEFI variables with some additional PCI related info (uses efibootmgr code internally)
- https://github.com/fpmurphy/Various/tree/master/uefivars-2.0 || uefivars-gitAUR
- efitools — Tools for manipulating UEFI secure boot platforms
- https://git.kernel.org/pub/scm/linux/kernel/git/jejb/efitools.git || efitools
- Ubuntu's Firmware Test Suite — Test suite that performs sanity checks on Intel/AMD PC firmware
- https://wiki.ubuntu.com/FirmwareTestSuite/ || fwts-gitAUR
efibootmgr
You will have to install the efibootmgr package.
Note:- If efibootmgr does not work on your system, you can reboot into #UEFI Shell and use
bcfg
to create a boot entry for the bootloader. - If you are unable to use
efibootmgr
, some UEFI firmwares allow users to directly manage UEFI boot entries from within its boot-time interface. For example, some firmwares have an 'Add New Boot Option' choice which enables you to select a local EFI system partition and manually enter the EFI application location e.g.EFIrefindrefind_x64.efi
. - The below commands use rEFInd boot manager as example.
To add a new boot option using efibootmgr you need to know three things:
- The disk containing the EFI system partition (ESP). E.g.:
/dev/sda
,/dev/nvme0n1
. - The partition number of the ESP on that disk. The
Y
in/dev/sdaY
or/dev/nvme0n1pY
. - The path to the EFI application (relative to the root of the ESP)
For example, if you want to add a boot option for /efi/EFI/refind/refind_x64.efi
where /efi
is the mount point of the ESP, run
In this example, this indicates that the ESP is on disk /dev/sda
and has partition number 1. The path to the EFI application relative to the root of the ESP is /EFI/refind/refind_x64.efi
. So you would create the boot entry as follows:
See efibootmgr(8) or efibootmgr README for more info.
as path separator but efibootmgr automatically converts UNIX-style /
path separators.UEFI Shell
The UEFI Shell is a shell/terminal for the firmware which allows launching EFI applications which include UEFI bootloaders. Apart from that, the shell can also be used to obtain various other information about the system or the firmware like memory map (memmap), modifying boot manager variables (bcfg), running partitioning programs (diskpart), loading UEFI drivers, editing text files (edit), hexedit etc.
Obtaining UEFI Shell
You can obtain a BSD licensed UEFI Shell from the TianoCore EDK2 project:
- Shell v2:
- On the Arch install medium:
/shellx64.efi
. A copy of/usr/share/edk2-shell/x64/Shell_Full.efi
from the time the ISO was built. - edk2-shell provides x86_64 Shell for x86_64 (64-bit) UEFI and IA32 Shell for IA32 (32-bit) UEFI - compiled directly from latest TianoCore EDK2 release.
- uefi-shell-gitAUR provides x86_64 Shell for x86_64 (64-bit) UEFI and IA32 Shell for IA32 (32-bit) UEFI - compiled directly from latest TianoCore EDK2 source.
- On the Arch install medium:
- Shell v1:
- Precompiled UEFI Shell v1 binaries from TianoCore (not updated anymore upstream as of Jan 10, 2014).
- Patched shells:
- Precompiled UEFI Shell v2 binary with bcfg modified to work with UEFI pre-2.3 firmware - from Clover EFI bootloader.
- Precompiled UEFI Shell v2 binary for compatibility with a broad range of firmwares - from the OpenCore bootloader. In the release archive:
EFI/OC/Tools/OpenShell.efi
.
Shell v2 works best in UEFI 2.3+ systems and is recommended over Shell v1 in those systems. Shell v1 should work in all UEFI systems irrespective of the spec. version the firmware follows. More information at ShellPkg and the EDK2 mailing list thread—Inclusion of UEFI shell in Linux distro iso.
Launching UEFI Shell
Few Asus and other AMI Aptio x86_64 UEFI firmware based motherboards (from Sandy Bridge onwards) provide an option called Launch EFI Shell from filesystem device. For those motherboards, copy the x86_64 UEFI Shell to the root of your EFI system partition, named as shellx64.efi
.
- The Arch Linux installation medium has
shellx64.efi
at the root of the volume. - rEFInd and systemd-boot will automatically add a boot menu entry for the UEFI shell if
shellx64.efi
is in the root of the EFI system partition.
Systems with Phoenix SecureCore Tiano UEFI firmware are known to have embedded UEFI Shell which can be launched using either F6
, F11
or F12
key.
/USB_drive_mointpoint/EFI/BOOT/BOOTX64.EFI
. This USB should come up in the firmware boot menu. Launching this option will launch the UEFI Shell for you.Important UEFI Shell commands
UEFI Shell commands usually support -b
option which makes output pause after each page. Run help -b
to list available internal commands. Available commands are either built into the shell or discrete EFI applications.
For more info see Intel Scripting Guide 2008 and Intel 'Course' 2011.
bcfg
bcfg
modifies the UEFI NVRAM entries which allows the user to change the boot entries or driver options. This command is described in detail in page 96 (Section 5.3) of the UEFI Shell Specification 2.2 document.
- Try
bcfg
only ifefibootmgr
fails to create working boot entries on your system. - UEFI Shell v1 official binary does not support
bcfg
command. See #Obtaining UEFI Shell for a modified UEFI Shell v2 binary which may work in UEFI pre-2.3 firmwares.
To dump a list of current boot entries:
To add a boot menu entry for rEFInd (for example) as 4th (numbering starts from zero) option in the boot menu:
where FS0:
is the mapping corresponding to the EFI system partition and FS0:EFIrefindrefind_x64.efi
is the file to be launched.
To add an entry to boot directly into your system without a bootloader, configure a boot option using your kernel as an EFISTUB:
where N
is the priority, V
is the volume number of your EFI system partition, and /dev/sdX#
is your root partition.
Clover Bootable Usb Windows
To remove the 4th boot option:
To move the boot option #3 to #0 (i.e. 1st or the default entry in the UEFI Boot menu):
For bcfg help text:
or:
map
map
displays a list of device mappings i.e. the names of available file systems (FS0
) and storage devices (blk0
).
Before running file system commands such as cd
or ls
, you need to change the shell to the appropriate file system by typing its name:
edit
edit
provides a basic text editor with an interface similar to nano, but slightly less functional. It handles UTF-8 encoding and takes care or LF vs CRLF line endings.
For example, to edit rEFInd's refind.conf
in the EFI system partition (FS0:
in the firmware),
Press Ctrl+e
for help.
UEFI drivers
This article or section needs expansion.
-r
/--driver
option. Mention rEFInd's file system drivers (and how it loads them), and also systemd-boot's planed feature. (Discuss in Talk:Unified Extensible Firmware Interface#)UEFI bootable media
Create UEFI bootable USB from ISO
Follow USB flash installation medium#BIOS and UEFI bootable USB.
Remove UEFI boot support from optical media
Note:- This section mentions removing UEFI boot support from a CD/DVD only (Optical Media booting via EL Torito), not from a USB flash drive.
- In order to hide the UEFI equipment on USB stick, use a partition editor after having copied the ISO to the flash drive. Remove the partition of type
EF
. Do not accept offers to convert to GPT.
Most of the 32-bit EFI Macs and some 64-bit EFI Macs refuse to boot from a UEFI(X64)+BIOS bootable CD/DVD. If one wishes to proceed with the installation using optical media, it might be necessary to remove UEFI support first.
Extract the ISO skipping the UEFI-specific directories:
Then rebuild the ISO, excluding the UEFI optical media booting support, using xorriso(1) from libisoburn. Be sure to set the correct volume label, e.g. ARCH_202103
; it can be acquired using file(1) on the original ISO.
Burn archlinux-version-x86_64-noUEFI.iso
to optical media and proceed with installation normally.
Booting 64-bit kernel on 32-bit UEFI
This article or section needs expansion.
initrd=
kernel's command line parameter.[4] It has been implemented in EDK2 OVMF[5][6] (version 202005 when built with LOAD_X64_ON_IA32_ENABLE
), so it can be tested using OVMF's builtin UEFI shell.[7] It can be speculated that archiso could be made bootable on IA32 UEFI if systemd-boot gains the capability of using this new booting method; see systemd issue 17056. (Discuss in Talk:Unified Extensible Firmware Interface#)Official ISO (Archiso) does not support booting on 32-bit (IA32) UEFI systems (FS#53182) since it uses EFISTUB (via systemd-boot boot manager for menu) for booting the kernel in UEFI mode. To boot a 64-bit kernel with 32-bit UEFI you have to use a boot loader that does not rely on EFI boot stub for launching kernels.
Using GRUB
Clover Bootable Usb Mojave
This section describes how to setup GRUB as the USB's UEFI bootloader.
- Create an editable USB Flash Installation.
- Create a GRUB standalone image for 32-bit UEFI systems by running the following commands:
Create Clover Bootable Usb
- Create
/mnt/EFI/boot/grub.cfg
with the following contents (replaceARCH_YYYYMM
with the ISO 9660 volume label e.g.ARCH_202010
):
- The ISO's volume label can be acquired using file(1).
- The given configuration entries can also be entered inside a GRUB command-shell.
During installation, in the boot loader installation step, install GRUB using the option --target=i386-efi
.
Testing UEFI in systems without native support
OVMF for virtual machines
OVMF is a TianoCore project to enable UEFI support for Virtual Machines. OVMF contains a sample UEFI firmware and a separate non-volatile variable store for QEMU.
You can install edk2-ovmf from the extra repository.
It is advised to make a local copy of the non-volatile variable store for your virtual machine:
To use the OVMF firmware and this variable store, add following to your QEMU command:
For example:
DUET for BIOS only systems
DUET was a TianoCore project that enabled chainloading a full UEFI environment from a BIOS system, in a way similar to BIOS OS booting. This method is being discussed extensively in https://www.insanelymac.com/forum/topic/186440-linux-and-windows-uefi-boot-using-tianocore-duet-firmware/. Pre-build DUET images can be downloaded from one of the repos at https://gitlab.com/tianocore_uefi_duet_builds/tianocore_uefi_duet_installer. Specific instructions for setting up DUET is available at https://gitlab.com/tianocore_uefi_duet_builds/tianocore_uefi_duet_installer/blob/master/Migle_BootDuet_INSTALL.txt . However, as of November 2018, the DUET code has been removed from TianoCore git repository.
You can also try https://sourceforge.net/projects/cloverefiboot/ which provides modified DUET images that may contain some system specific fixes and is more frequently updated compared to the gitlab repos.
Troubleshooting
Windows 7 will not boot in UEFI mode
If you have installed Windows to a different hard disk with GPT partitioning and still have a MBR partitioned hard disk in your computer, then it is possible that the firmware (UEFI) is starting its CSM support (for booting MBR partitions) and therefore Windows will not boot. To solve this merge your MBR hard disk to GPT partitioning or disable the SATA port where the MBR hard disk is plugged in or unplug the SATA connector from this hard disk.
Mainboards with this kind of problem:
- Gigabyte Z77X-UD3H rev. 1.1 (UEFI version F19e)
- The firmware option for booting 'UEFI Only' does not prevent the firmware from starting CSM.
Windows changes boot order
If you dual boot with Windows and your motherboard just boots Windows immediately instead of your chosen EFI application, there are several possible causes and workarounds.
To boot back into Arch Linux when you are stuck with Windows, reach Advanced startup in Windows by the Windows PowerShell command shutdown /r /o
, or via Settings > Update & Security > Recovery > Advanced startup and select Restart now. When you have reached the Advanced startup menu, choose Use a device, which actually contains your UEFI boot options (not limited to USB or CD, but can also boot operating system in hard drive), and choose 'Arch Linux'.
- Ensure Fast Startup is disabled in your Windows power options
- Ensure Secure Boot is disabled in your firmware (if you are not using a signed boot loader)
- Ensure your UEFI boot order does not have Windows Boot Manager set first e.g. using efibootmgr and what you see in the configuration tool of the UEFI. Some motherboards override by default any settings set with efibootmgr by Windows if it detects it. This is confirmed in a Packard Bell laptop.
- If your motherboard is booting the default boot path (
EFIBOOTBOOTX64.EFI
), this file may have been overwritten with the Windows boot loader. Try setting the correct boot path e.g. using efibootmgr. - If the previous steps do not work, you can tell the Windows boot loader to run a different EFI application. From a Windows administrator command prompt
bcdedit /set '{bootmgr}' path 'EFIpathtoapp.efi'
- Alternatively, deactivate the Windows Boot Manager by running
efibootmgr -A -b bootnumber
as root. Replacebootnumber
with the actual Windows Boot Manager boot number; you can see it by runningefibootmgr
with no options. - Alternatively, you can set a startup script in Windows that ensures that the boot order is set correctly every time you boot Windows.
- Open a command prompt with administrator privileges. Run
bcdedit /enum firmware
and find your desired boot entry. - Copy the identifier, including the brackets, e.g.
{31d0d5f4-22ad-11e5-b30b-806e6f6e6963}
- Create a batch file with the command
bcdedit /set '{fwbootmgr}' DEFAULT '{copied-boot-identifier}'
- Open gpedit.msc and under Local Computer Policy > Computer Configuration > Windows Settings > Scripts (Startup/Shutdown), choose Startup
- Under the Scripts tab, choose the Add button, and select your batch file
- Open a command prompt with administrator privileges. Run
USB media gets struck with black screen
This issue can occur due to KMS issue. Try Disabling KMS while booting the USB.
UEFI boot loader does not show up in firmware menu
On certain UEFI motherboards like some boards with an Intel Z77 chipset, adding entries with efibootmgr
or bcfg
from the UEFI Shell will not work because they do not show up on the boot menu list after being added to NVRAM.
This issue is caused because the motherboards can only load Microsoft Windows. To solve this you have to place the .efi file in the location that Windows uses.
Copy the bootx64.efi
file from the Arch Linux installation medium (FSO:
) to the Microsoft directory your ESP partition on your hard drive (FS1:
). Do this by booting into EFI shell and typing:
After reboot, any entries added to NVRAM should show up in the boot menu.
System boots to EFI shell after hardware change or starting other operating system
This article or section needs language, wiki syntax or style improvements. See Help:Style for reference.
EFI stores state on the motherboard, called EFIVARS. Your bootloader (e.g. GRUB) may need to set up these variables in a certain way in order to boot. If your hardware configuration changes, your motherboard is replaced, or you boot into another operating system which overwrites these variables (Windows), you may be dumped into the EFI shell or boot menu (where your device is not listed). Upon attempting to boot Arch Linux since the EFIVARS are incorrect and EFI can no longer find your bootloader.
At this point, you can use the EFI shell to find and boot your bootloader manually. Usually something like:
To prevent booting into the EFI shell again, you can install your bootloader to the default EFI boot location. To do this with GRUB's grub-install
, see GRUB#Default/fallback boot path.
There is no guaranteed success for the 'Default/fallback boot path' method. Some board firmware (for example AsRock C2550D4I and C2750D4I) will search and boot the default locations on removable drives only. Booting from non removable drives (such as internal HDD, NVMe, etc.) requires fixing the efivars. For example using efibootmgr
:
Boot entries created with efibootmgr fail to show up in UEFI
efibootmgr can fail to detect EDD 3.0 and as a result create unusable boot entries in NVRAM. See efibootmgr issue 86 for the details.
To work around this, when creating boot entries manually, add the -e 3
option to the efibootmgr command. E.g.
To fix boot loader installers, like grub-install
and refind-install
, create a wrapper script /usr/local/bin/efibootmgr
and make it executable:
See also
Clover Bootable Usb High Sierra
- UEFI Forum - contains the official UEFI Specifications - GUID Partition Table is part of UEFI Specification
- Intel's TianoCore Project for Open-Source UEFI firmware which includes DuetPkg for direct BIOS based booting and OvmfPkg used in QEMU and Oracle VirtualBox