# Limine ### What is Limine? Limine is an advanced x86/x86_64 BIOS/UEFI Bootloader which supports *modern* PC features such as Long Mode, 5-level paging, and SMP (multicore), to name a few. ### Limine's boot menu ![Reference screenshot](/screenshot.png?raw=true "Reference screenshot") [Photo by Nishant Aneja from Pexels](https://www.pexels.com/photo/close-up-photo-of-waterdrops-on-glass-2527248/) ### 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 * FAT16/32 * ISO9660 (CDs/DVDs) ### Supported partitioning schemes * MBR * GPT * Unpartitioned media ## Warning about using `trunk` Please refrain from using the `trunk` branch of this repository directly, unless you have a *very* good reason to. The `trunk` branch is unstable, and non-backwards compatible changes are made to it routinely. Use instead a [release](https://github.com/limine-bootloader/limine/releases), or a [release branch](https://github.com/limine-bootloader/limine/branches) (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 ```bash git clone https://github.com/limine-bootloader/limine.git --branch=v1.0 ``` (replace `v1.0` with the chosen release) or a release branch with ```bash 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 `trunk` does not reflect the documentation for the specific releases, and one should refer to the releases' respective documentation instead, contained in their files. ## Building ### Building the bootloader 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: ```bash make toolchain ``` *The above step may take a while* After that is done, the bootloader itself can be built with: ```bash make ``` The generated bootloader files are going to be in `bin`. ### Installing Limine binaries This step is optional as the bootloader binaries can be used from the `bin` directory just fine. This step will only install them in a `share` and `bin` directories in the specified `PREFIX` (default is `/usr/local`). Use `make install` to install Limine binaries, optionally specifying a prefix with a `PREFIX=...` option. ## How to use ### UEFI The `BOOTX64.EFI` file is a vaild EFI application that can be simply copied to the `/EFI/BOOT` directory of a FAT32 formatted EFI system partition. This file can be installed there and coexist with a BIOS installation of Limine (see below) so that the disk will be bootable by both BIOS and UEFI. The boot device must to contain the `limine.cfg` file in either the root or the `boot` directory of one of the partitions, formatted with a supported file system (the ESP partition is recommended). ### BIOS/MBR In order to install Limine on a MBR device (which can just be a raw image file), run `limine-install` as such: ```bash limine-install ``` The boot device must to contain the `limine.sys` and `limine.cfg` files in either the root or the `boot` directory of one of the partitions, formatted with a supported file system. ### BIOS/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: ```bash limine-install <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. The boot device must to contain the `limine.sys` and `limine.cfg` files in either the root or the `boot` directory of one of the partitions, formatted with a supported file system. ### BIOS CD-ROM ISO creation In order to create a bootable ISO with Limine, place the `limine-cd.bin`, `limine.sys`, and `limine.cfg` files into a directory which will serve as the root of the created ISO. (`limine.sys` and `limine.cfg` must either be in the root or inside a `boot` subdirectory; `limine-cd.bin` can reside anywhere). Place any other file you want to be on the final ISO in said directory, then run: ``` genisoimage -no-emul-boot -b \ -boot-load-size 4 -boot-info-table -o myiso.iso ``` *Note: `genisoimage` is usually part of the `cdrtools` package.* `` is the relative path of `limine-cd.bin` inside the root directory. For example, if it was copied in `/boot/limine-cd.bin`, it would be `boot/limine-cd.bin`. ### BIOS/PXE boot The `limine-pxe.bin` binary is a valid PXE boot image. In order to boot Limine from PXE it is necessary to setup a DHCP server with support for PXE booting. This can either be accomplished using a single DHCP server or your existing DHCP server and a proxy DHCP server such as dnsmasq. `limine.cfg` and `limine.sys` are expected to be on the server used for boot. ### Configuration The `limine.cfg` file contains Limine's configuration. 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: ```bash 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.sys limine.sys 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 ... 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](https://github.com/jibsen/tinf). ## Discord server We have a [Discord server](https://discord.gg/QEeZMz4) if you need support, info, or you just want to hang out with us.