Leah Rowe
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1ea2893e03
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040249ca74
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@ -3,6 +3,44 @@ title: Installation instructions
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x-toc-enable: true
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...
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**GRUB payload warning**
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====================
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Firstly, it should be stated: in almost all cases, GRUB works just fine, on
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all of the machines that we test, but as of 26 May 2024 we got the error
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report:
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See: <https://codeberg.org/libreboot/lbmk/issues/216>
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Although we've only seen this thus far (as per user reports) on Intel
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SandyBridge based Dell Latitude laptops, we advise:
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**DO NOT use a ROM image where GRUB is the first payload. If you want to
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use the GRUB payload, please use a ROM image with `seabios_` at the start
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of the file name. Avoid images with `grub_` at the start of the file name.**
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ROM images with `grubonly` in them should also be avoided; if you want GRUB
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to be the first thing you see (without interruption), use a ROM image
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with `seabios_` at the start of the file name, and `grubfirst` at the end;
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these place a bootorder file in CBFS, so that SeaBIOS loads GRUB first, but
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you can still press ESC to bring up the SeaBIOS boot select menu.
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The error above, in the linked bug report, occurs on `grub_free()`
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or `grub_realloc()` and could be caused by anything in GRUB; the user tested
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on memtest86plus and got no errors, and SeaBIOS works; BIOS GRUB (from a distro)
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also works, where GRUB doesn't need as many drivers; we suspect this may be
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a use-after-free in a GRUB driver, or otherwise something writing to heap memory
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wrongly. The bug is not yet known, only the symptom (the fatal error message).
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Libreboot releases after 20240504 will *only* (on x86) contain ROM images where
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SeaBIOS is the first payload, without disabling the SeaBIOS menu (no `grubonly`). You'll still be able to use GRUB, either by pressing ESC for the boot
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select menu, and/or using an image with `grubfirst` in the file name so that
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SeaBIOS loads it first (while still permitting boot select via ESC keypress).
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GRUB's code is vast, and complicated, so this policy change is permanent,
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until GRUB can be well-audited (likely forked, with dead/legacy code removed).
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SeaBIOS code is much smaller and more robust. Remember always: code equals bugs.
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Need help?
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==========
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@ -199,48 +237,16 @@ an option in the boot menu.
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ROM images that have `seabios_withgrub` in the file name start with SeaBIOS
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first, but also have GRUB available in the boot menu when you press ESC.
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### seabios\_grubfirst (DEFUNCT)
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**DEFUNCT**
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This build option is obsolete, and should not be used. It was deleted
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in lbmk revision `e1bbdadc9584291cf062660d67128e9f17ab788e`.
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It was believed, in earlier theory, that VGA ROM initialisation could
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be used in SeaBIOS and then SeaBIOS boots into a GRUB payload (built
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for coreboot), where the initialisation would continue to be used, but
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it didn't work that way.
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It's best to use PC GRUB (normal BIOS GRUB), but compile it into a floppy
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image to insert inside CBFS, to then be executed by SeaBIOS. This is referred
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to as SeaGRUB by the Libreboot project, and it would be quite useful
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for desktop users, but it's largely irrelevant on laptops where
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coreboot's own `libgfxinit` is usually available (or the option ROM is
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easy to extract from vendor firmware and insert).
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Where direct bare metal GRUB is desired, but you use a desktop system with
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an add-on graphics card, you must extract the VGA ROM for your card and
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insert it into the coreboot ROM, for coreboot itself to execute. This will
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require custom configuration on your part, and it is thus beyond the scope
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of the Libreboot project, in context of lbmk (automated build system).
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Some older Libreboot releases included ROM images built using this option,
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and those specific ROM images (`seabios_grubfirst` ones) should not be
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used; you should only use `seabios_grubfirst` or `seabios`, in most
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scenarios, if SeaBIOS is required.
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For most desktop users, if running an external graphics card, it's easier
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to simply boot in text mode with a SeaBIOS payload and use only that. This
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will Just Work with almost all graphics cards, allowing you to use an
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operating system with a full display and (drivers permitting) full 2D/3D
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acceleration.
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ROM images with this and `grubonly` in the image start SeaBIOS, but only load
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GRUB from SeaBIOS and the SeaBIOS menu is disabled. Use these images if you
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only want GRUB; they are provided on systems that only have VGA ROM-based
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initialisation, usually discrete graphics cards on desktop machines.
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Which systems are supported?
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============================
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[Refer to the hardware compatibility page](../hardware/)
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Sandy/Ivybridge/Haswell MAC address (e.g. X230, X220, T440p, W541, hp8200sff)
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Intel GbE MAC address (IFD-based systems)
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=====================================================================
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