Payloads

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coreboot in itself is "only" minimal code for initializing a mainboard with peripherals. After the initialization, it jumps to a payload.

Payloads

Bootloaders

SeaBIOS

SeaBIOS is an open-source implementation of the standard bootstrap callback layer implemented by an x86 bios. It enables booting from unmodified cdroms and hard drives.

SeaBIOS has been tested with Linux, NetBSD, FreeDOS, and Windows XP/Vista/7. Classic GRUB, lilo, and isolinux work well with SeaBIOS. Other x86 bootloaders and operating systems will likely also work.

Official GRUB 2

GRUB 2 is the official version 2 of GNU GRUB.

You can use the official GRUB 2 as a coreboot payload, in order to boot and operating system from a hard drive, for instance.

GRUB2

An old version of GRUB2 with coreboot and crypto support.

You can use GRUB2 as a coreboot payload, too, in order to boot and operating system from a hard drive, for instance.

FILO

FILO is a simple bootloader with filesystem support.

Etherboot

Etherboot is a network bootloader. It provides a direct replacement for proprietary PXE ROMs, with many extra features such as DNS, HTTP, iSCSI, etc.

Older versions of Etherboot included parts of FILO, and thus supported SATA and USB booting.

The new GPXE is not yet supported directly, various code changes are required before it can work as a coreboot payload. (Note, GPXE works well when run with SeaBIOS.)

Open Firmware

Mitch Bradley's Open Firmware, an IEEE1275-1994 Open Firmware implementation, can also be used as coreboot payload.

OpenBIOS

OpenBIOS — IEEE1275-1994 Open Firmware.

Tiano Core

Tianocoreboot.png

Tiano Core is a bootloader providing the UEFI interface. See http://www.tianocore.org/ for more information.


Operating systems

Linux

Coreboot can use a Linux kernel as payload directly. That is, the kernel is included in the ROM chip where coreboot resides.

Alternatively, you can also boot a Linux kernel from your hard drive using either the FILO, GRUB2, or SeaBIOS payloads.

FreeBSD

FreeBSD can be booted via coreboot with the help of ADLO.

OpenBSD

OpenBSD can also be booted via coreboot with the help of ADLO.

This use-case is not well-tested yet, though.

NetBSD

NetBSD/x86 boot code is known to work with SeaBIOS.

jakllsch has worked on a partially-complete port of the x86 boot code to the role of native payload. However, with the advent of SeaBIOS, this is likely to become less of a priority. Consult Coreboot and NetBSD for further information.

Windows

Windows can be booted with the help of SeaBIOS.

We have successfully booted Windows XP, Windows Vista and Windows 7 (Beta).

OpenSolaris

OpenSolaris has multiboot compliant kernels, and so it is possible to boot it with GRUB2 (pending some bug fixes). Some Sun engineers even worked on it, see http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6475349 for information.

Currently, GRUB2 refuses to load the kernel due to a small bug in the multiboot header of the kernel, but the kernel still refuses to work if that is worked around. Maybe they reintroduced some BIOS calls again?

See also this blog entry.

Other

Memtest86 / Memtest86+

Qemu memtest.png

Memtest86 is a program which checks your RAM modules.

It can be run from within GRUB, but also as a coreboot payload (i.e. included in your ROM chip).


ADLO

ADLO — Glue layer to 16-bit Bochs BIOS. Allows booting Windows and OpenBSD. Superseded by SeaBIOS.

Libpayload

Libpayload is a helper-library for payload-writers.

Coreinfo

Coreinfo pci.png

coreinfo is a coreboot payload which can display various system information.

Bayou

Bayou-screenshot-menu.jpg

Bayou is the working name for a coreboot payload that can choose, load and run other payloads from a LAR archive on the ROM.

Games

GRUB invaders

Coreboot invaders.png

GRUB invaders multi-boot compliant space invaders game.

It can either be started from within GRUB (as a "kernel"), or it can be used as a coreboot payload.


TINT

Coreboot libpayload tint.png

tint is a falling blocks game.

Possible future payloads

The following payloads might or might not work (with more or less changes required) with coreboot — their usage hasn't been tested or documented so far.

  • CodeGen's SmartFirmware — IEEE1275-1994 Open Firmware
  • GNUFI (UEFI)
  • Plan 9 — A distributed operating system.
  • RedBoot / eCos — Real-time OS for embedded systems; initial port to ELF completed but no longer available.
  • GPXE — Needs some code changes
  • HelenOS
  • ReactOS
  • FreeDOS
  • DragonflyBSD
  • MirBSD
  • MidnightBSD
  • OpenSolaris / BeleniX
  • FreeRTOS
  • QNX
  • Windows CE
  • Haiku
  • NanoVM (small JVM)
  • uip / lwip (small TCP/IP stacks)
  • MenuetOS
  • Minix

History

The payload was originally intended to be a Linux kernel stored in flash. Flash ROM growth rate was anticipated optimistically however, today there are not many mainboards that actually have enough flash ROM room for a kernel. 512KB can be seen here-and-there and a few boards come with 1MB. Recent kernels really want that MB, and then you'll only have room for 300-400 KB of initial ramdisk, which could be too small too, depending on the application. During testing, a payload may also be downloaded via X-Modem from the serial debug console, saving flashing time.

So, other payloads are used; the two major ones are FILO (soon to be deprecated in favor of GRUB2) and Etherboot (soon to be deprecated in favor of GPXE). FILO loads a kernel from a filesystem on an IDE device and Etherboot loads a kernel from the network or from a filesystem on an IDE device.

If you're using FILO there is no Linux kernel until FILO loads it, and the kernel loaded by FILO (or Etherboot) can absolutely be the one you want to run in your system. Just set it up with the correct root and init commandline so that it can start init.