# 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 ![their specifications](https://github.com/stivale/stivale) for details) * Chainloading ### Supported filesystems * ext2/3/4 * echfs * FAT16/32 * ISO9660 (CDs/DVDs) ### Supported partitioning schemes * MBR * GPT * Unpartitioned media ## Binary releases For convenience, for point releases, binaries are distributed. These binaries are shipped in the `-binary` branches and tags of this repository (see [branches](https://github.com/limine-bootloader/limine/branches/all) and [tags](https://github.com/limine-bootloader/limine/tags)). For example, to clone the latest binary release of the `v2.x` branch one can do ```bash git clone https://github.com/limine-bootloader/limine.git --branch=v2.0-branch-binary --depth=1 ``` or, to clone a specific binary point release (for example v2.1.6) ```bash git clone https://github.com/limine-bootloader/limine.git --branch=v2.1.6-binary --depth=1 ``` Additionally, the absolute latest Limine binary release can be obtained by fetching the `latest-binary` branch: ```bash git clone https://github.com/limine-bootloader/limine.git --branch=latest-binary --depth=1 ``` `limine-install` binaries are provided for Linux and Windows. In case one wants to rebuild `limine-install`, simply use `make` in the binary release. ## Building the bootloader *These steps are not necessary if cloning a binary release. If so, skip to* *"Installing Limine binaries".* ### Building the toolchain This step can take a long time, but it will ensure that the compiler will work with Limine. If on an x86_64 host, with GCC installed, you can also skip to the next paragraph. The toolchain building process depends on the following packages: `make`, `wget`, `gcc`, `g++`, `binutils`. Building the toolchain can be accomplished by running: ```bash make toolchain ``` *The above step may take a while* ### Building Limine In order to build Limine, the following packages have to be installed: `make`, `git`, `which`, `nasm`, `mtools`. Furthermore, either the toolchain must have been built in the previous paragraph, or `gcc` and `binutils` must also be installed. The bootloader can then be built with: ```bash make ``` It is possible to pass `make` additional flags, most relevantly, `TOOLCHAIN=` which allows one to specify an alternative toolchain for the build system to use (the default is `x86_64-elf`, falling back to no-triple, or host, toolchain). 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` or release 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 BIOS 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: ``` xorriso -as mkisofs -b \ -no-emul-boot -boot-load-size 4 -boot-info-table -o image.iso ``` *Note: `xorriso` is required.* `` 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`. ### UEFI CD-ROM ISO creation In order to create a bootable UEFI ISO with Limine, place the `limine-eltorito-efi.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-eltorito-efi.bin` can reside anywhere). Place any other file you want to be on the final ISO in said directory, then run: ``` xorriso -as mkisofs -eltorito-alt-boot -e \ -no-emul-boot -o image.iso ``` *Note: `xorriso` is required.* `` is the relative path of `limine-eltorito-efi.bin` inside the root directory. For example, if it was copied in `/boot/limine-eltorito-efi.bin`, it would be `boot/limine-eltorito-efi.bin`. ### BIOS+UEFI CD-ROM ISO creation Additionally, it is possible to combine the 2 aformentioned commands into a single one in order to create a CD ISO which will boot on both BIOS and UEFI: ``` xorriso -as mkisofs -b \ -no-emul-boot -boot-load-size 4 -boot-info-table \ -eltorito-alt-boot -e \ -no-emul-boot -o image.iso ``` ### 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.