Questions tagged [grub]

GENERAL GRUB SUPPORT IS OFF-TOPIC. Support questions may be asked on https://superuser.com. GRUB, the GNU GRand Unified Bootloader, is a boot loader used on x86 systems, typically used to boot Linux. Questions about using or configuring GRUB are rarely on-topic for Stack Overflow outside of unusual circumstances.

GRUB is the reference implementation of the Multiboot Specification, which provides a user the choice to boot one of multiple operating systems installed on a computer or select a specific kernel configuration available on a particular operating system's partitions.

As GRUB is not a tool specifically used for software development, questions about it will typically be considered off-topic on Stack Overflow unless it is being used in a particularly unusual manner, e.g. if you are developing custom modules for GRUB, or if you have developed your own operating system kernel.

If you are having a problem with using or configuring GRUB on your computer, please consider asking your question on SuperUser.com, the Stack Exchange site for computer enthusiasts and power users, or on a site specific to the Linux distribution you are using, such as the Ask Ubuntu Stack Exchange or UNIX & Linux Stack Exchange.

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GRUB set address kernel is loaded at

How would I go about changing the address GRUB tries to load my kernel at without using the linker? I would like to do this from GRUB config files.
DrCarnivore
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Debugging C: GDB returns "address where has been loaded is missing"

I'm very new to the C language and have been tasked with modifying GRUB. What a way to learn, right? Anyway, I'm trying to debug my modified GRUB using VMWare and GDB. I've been able to get the debugger working before, but for some reason, every…
Harin
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add git to yocto image

for development I want to add git to my yocto image. So I add IMAGE_INSTALL += "git" to my `local.conf. But when I run qemu I run into this crash straigth away: Welcome to GRUB! lock: OK lock: OK error: file `/boot/bzImage' not found. Dropping…
grmmgrmm
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Why won't grub boot immediately into Ubuntu?

I want to boot directly into my Xubuntu. I searched a bit online and found out that you can edit the file /etc/default/grub to make the timeout of GRUB 0 seconds. What you have to do is change GRUB_TIMEOUT to 0 and then in your shell run sudo…
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How To Call ExitBootService through GRUB

I am working on a UEFI Based Hypervisor for Intel x86 platform. The GRUB is being used to load both the VMM and OS images, for reducing the complexity I am currently loading only one GPOS through GRUB and obviously the VMM. However due to some…
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GRUB invalid multiboot

I am writing a simple 32-bit kernel. I'm booting with GRUB. Here is the code: #include #include #include #include #include #include #include #include…
SpilledMango
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Pexpect and GRUB - Why is Pexpect showing me a blank GRUB menu?

I am attempting to script a reboot of a system and I have several GRUB entries. Pexpect doesn't seem to "see" the menu items. Here is a code snippet: def get_menu_selections(xtn): print "Waiting for GNU GRUB to show" xtn.expect_exact("GNU…
harperville
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What are meaning of the global variables specified for multiboot for GRUB boot loader

I am trying so hard to figure out what this does .set ALIGN, 1<<0 # align loaded modules on page boundaries .set MEMINFO, 1<<1 # provide memory map .set FLAGS, ALIGN | MEMINFO # this is the Multiboot 'flag' field .set…
Nikola Jokic
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How Grub (legacy) recognizes and processes various file systems?

I have been reading about Grub legacy boot loader. And what struck me is how Grub handles file systems. Grub supports a large subset of file systems. My doubt is, How Grub recognizes these file systems from one another? Even if they are recognized,…
Panther Coder
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GRUB memory layout

I am trying to get the grub memory layout using the Multiboot Header. The code is like this memory_map_t *getmmap(memory_map_t *memMap) { uint32_t i = 0; multiboot_info_t *mbt; memory_map_t *mmap =…
ashish
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Query regarding main() of GRUB

Below is the code of main() of grub. Here I want to know about this line: file = fopen(arg_v[1], "rb"); Here which file fopen is opening? What file this arg v[1] is pointing to? int main(unsigned arg_c, char *arg_v[]) { FILE *file; …
narayanpatra
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How does the memory behind statically allocated huge pages get distributed across NUMA nodes?

In my /etc/default/grub file I have explicitly set aside N huge pages with "hugepages=N". If I'm running on a box with 2 NUMA nodes, does N/2 huge pages get set aside for each node, or do they all go to node 0, or ....? Also is there a way on the…
Joseph Garvin
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How to add a menu entry in Grub to start Ubuntu in command line

I have a desktop that I sometimes only use remotely through SSH. In these cases, having a graphical interface is useless so it could be great to start the system in text mode. I'm using Ubuntu and I wanted to add a menu entry in Grub to do what I…
Jeremy
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Found unknown Linux distribution on /dev/sdb2: grub configuration dual boot Arch Linux and NetBSD-7.0

I have Arch Linux on /dev/sdb1 and NetBSD-7.0 on /dev/sdb2. On Arch Linux when I run sudo grub-mkconfig -o /boot/grub/grub.cfg I get a message like Found unknown Linux distribution on /dev/sdb2 but when I reboot, there is no grub option for that…
Megidd
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Expect script to select options in GRUB menu

Is it possible to select options in GRUB menu to select appropriate option to boot the device ? I have a serial connection to the device and I am writing the expect script to send the DOWNARROW key to select the appropriate option in the GRUB menu…
codingfreak
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