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Questions tagged [uefi]

The Unified Extensible Firmware Interface (UEFI) is a specification that defines a software interface between an operating system and platform firmware. UEFI is meant to replace the Basic Input/Output System (BIOS) firmware interface.

The Unified Extensible Firmware Interface (UEFI) is a specification that defines a software interface between an operating system and platform firmware. UEFI is meant to replace the Basic Input/Output System (BIOS) firmware interface.

For more information see:

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How to create a UEFI kernel in NASM on Linux

I have been following this guide for OS development OS Development on Windows However, I do not like the windows development environment, and so I am trying to transfer these instructions over to my preferred Linux environment. I have tried the…
Jonathan Dewein
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Unresolved external symbol __aullshr when optimization is turned off

I am compiling a piece of UEFI C code with Visual Studio 2015 C/C++ compiler. The compiler is targeting IA32, not X64. When turning on the optimization with "/O1", the build is OK. When turning off the optimization with "/Od", the build gives below…
smwikipedia
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Debugging UEFI with QEMU on Windows

I apologize for my English. I want to debug UEFI applications using WinDbg and UEFI (which will run OVMF). How I try to run: Collect the image OVMF defining in the file .dsc macros source_debug_enable debug_on_serial_port Copy the OVMF.fd file to…
user8824256
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genisoimage and UEFI

How can I create UEFI ISO image on Debian Jessie machine? When I use follow command on my Kubuntu everything is OK genisoimage -quiet -V "my-amd64" -J -R -r -l -cache-inodes -c isolinux/boot.cat -b isolinux/isolinux.bin -no-emul-boot…
Kolesar
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Adding UEFI firmware boot entry using bcdedit

How to add a new UEFI firmware boot menu entry(in NVRAM) using bcdedit. For e.g. I tried the following steps but boot entry is not getting added. bcdedit /create /d "LinuxLoader" /application osloader this will return a new guid (say…
Raghu
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Chainloading Windows-EFI from Linux-EFI

Currently, I have the following boot chain in legacy (MBR) mode: GRUB2 -> Linux -> kexec to Grub4Dos -> Windows. I'm trying to figure out if this is also possible in UEFI-mode, i.e. starting the windows EFI loader from Linux-EFI. The problem…
neusdan
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switch from 64-bit long mode to 32-bit compatibility mode on x64

I want to switch from 64-bit long mode to 32-bit compatibility mode (and back) in a UEFI boot application. Changing bit L in the code segment descriptor seems not enough. What are the other steps? Is there an example?
user2707695
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What is the difference between FS0 and BLK0 in UEFI shell mappings?

I think FS stands for filesystem, but I don't know what BLK stands for. Not only that, but what are the meanings behind the pci hierarchy parameters. i.e. When I see HD(1,MBR,0x0003B) what does "1","MBR", and what looks to be an address, stand…
SlyGuy
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How to access command line arguments in UEFI?

What part of the specification details how command line arguments can be obtained?
user773099
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Move Google Cloud Compute instance between zones

I have a Compute Engine instance on Google Cloud on zone europe-west3-c. In last several days, when I try to start it I get following message: The zone 'projects/PROJECT/zones/europe-west3-c' does not have enough resources available to fulfill the…
francosy
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Who enables the A20 line when booting in pure UEFI?

Is this handled by the UEFI firmware or by for the GRUB grubx64.efi bootloader? I looked at https://wiki.osdev.org/UEFI which claims: UEFI firmware ... also prepares a protected mode environment with flat segmentation and for x86-64 CPUs, a long…
user10607
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What is the correct way to load a UEFI protocol?

Apologies if this doesn't fit the StackOverflow format. I'm currently learning about writing UEFI applications. I've been reading the UEFI standard as well as a wealth of tutorials online and I can't seem to figure out what is the correct method for…
ajxs
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How is an efi application being set as the bootloader through code?

By following this tutorial, I am able to create a simple efi application that prints hello world when executed from an uefi shell. However, I was wondering how does one creates bootable EFI image. I tried to use bcfg command in the shell and added…
Andrew Shi
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Changing boot order for UEFI in c#

Im trying to change the boot order to all my Toshiba's The vendor said i could use SetFirmwareEnvironmentVariable() to do this. So i have found the code and generated this static void Main(string[] args) { //Set the variables for the…
New Bee
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Can't load self-compiled linux kernel

I compiled a linux kernel from source code which version is 4.8.5. Everything is OK during compiling but I just can't get it loaded. After I choose 4.8.5 when asked to select a kernel version, it soon runs into trouble and the screen just…
tuan long
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