Limine

What is Limine?

Limine is an advanced x86/x86_64 BIOS Bootloader which supports modern PC features such as Long Mode, 5-level paging, and SMP (multicore), to name a few.

Limine's boot menu

Photo by Nishant Aneja from Pexels

Supported boot protocols

• Linux
• stivale and stivale2 (Limine's native boot protocols, see STIVALE{,2}.md for details)
• Chainloading

Supported filesystems

• ext2/3/4
• echfs
• FAT32

Supported partitioning schemes

• MBR
• GPT

Warning about using unstable

Please refrain from using the unstable branch of this repository directly, unless you have a very good reason to. The unstable branch is unstable, and non-backwards compatible changes are made to it routinely.

Use instead a release, or a release branch (like v1.0-branch).

Following a release offers a fixed point, immutable snapshot of Limine, while following a release branch tracks the latest changes made to that major release's branch which do not break compatibility (but could break in other, non-obvious ways).

One can clone a release directly using

git clone https://github.com/limine-bootloader/limine.git --branch=v1.0

(replace v1.0 with the chosen release)

or a release branch with

git clone https://github.com/limine-bootloader/limine.git --branch=v1.0-branch

(replace v1.0-branch with the chosen release branch)

Also note that the documentation contained in unstable does not reflect the documentation for the specific releases, and one should refer to the releases' documentation instead, contained in their files.

Building

Building the bootloader

Building the bootloader is not necessary as a prebuilt copy is shipped in this repository (limine.bin).

Should one want to build the bootloader to make sure the shipped copy is authentic, to develop, to debug, or any other reason, it is necessary to first build the set of tools that the bootloader needs in order to be built.

This can be accomplished by running:

make toolchain

The above step may take a while

After that is done, the bootloader itself can be built with:

make bootloader

A newly generated limine.bin image should now be present in the root of the repo.

This newly built image should match 1:1 (aka, same checksum) with the one shipped with the respective commit.

Compiling limine-install

To build the limine-install program, simply run make in the root of the repo. This will embed the limine.bin bootloader image from the repository's root into limine-install, ready to be deployed to a device.

Then use make install to install it, optionally specifying a prefix with a PREFIX=... option.

Installing limine-install is optional as it can also be used from the root of the repository just fine.

How to use

MBR

In order to install Limine on a MBR device (which can just be a raw image file), run the limine-install as such:

limine-install <path to device/image>

GPT

If using a GPT formatted device, there are 2 options one can follow for installation:

• Specifying a dedicated stage 2 partition.
• Letting limine-install attempt to embed stage 2 within GPT structures.

In case one wants to specify a stage 2 partition, create a partition on the GPT device of at least 32KiB in size, and pass the 1-based number of the partition to limine-install as a second argument; such as:

limine-install <path to device/image> <1-based stage 2 partition number>

In case one wants to let limine-install embed stage 2 within GPT's structures, simply omit the partition number, and invoke limine-install the same as one would do for an MBR partitioned device.

Configuration

Then make sure the device/image contains at least 1 partition formatted in a supported filesystem containing a /limine.cfg or /boot/limine.cfg file and the kernel/modules one wants to load.

An example limine.cfg file can be found in test/limine.cfg.

More info on the format of limine.cfg can be found in CONFIG.md.

Example

For example, to create an empty image file of 64MiB in size, 1 echfs partition on the image spanning the whole device, format it, copy the relevant files over, and install Limine, one can do:

dd if=/dev/zero bs=1M count=0 seek=64 of=test.img
parted -s test.img mklabel msdos
parted -s test.img mkpart primary 1 100%
parted -s test.img set 1 boot on # Workaround for buggy BIOSes

echfs-utils -m -p0 test.img quick-format 32768
echfs-utils -m -p0 test.img import path/to/limine.cfg limine.cfg
echfs-utils -m -p0 test.img import path/to/kernel.elf kernel.elf
echfs-utils -m -p0 test.img import <path to file> <path in image>
...
limine-install test.img

One can get echfs-utils by installing https://github.com/echfs/echfs.

Acknowledgments

Limine uses a stripped-down version of tinf.

Discord server

We have a Discord server if you need support, info, or you just want to hang out with us.