deprecation notice, regarding seabios_grubfirst

hslick-master
Leah Rowe 2022-11-22 23:02:11 +00:00
parent 8f87a236f7
commit 33dc596206
2 changed files with 41 additions and 7 deletions

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@ -110,6 +110,13 @@ documentation.
If you're flashing a ROM for a machine where `seabios_withgrub`
and `seabios_grubfirst` ROMs are available, choose `seabios_withgrub`.
DO NOT USE ROM IMAGES WITH `seabios_grubfirst` IN THE FILE NAME! These were
present in older Libreboot releases, and supported in previous revisions
of the build system, but they did not work for the intended purpose. More
info is written on the [Libreboot installation guide](../install/). ROM
images with `seabios_grubfirst` in the filename will NOT be included in
future Libreboot releases.
Dubious mention: Tianocore
--------------------------

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@ -109,14 +109,41 @@ an option in the boot menu.
ROM images that have `seabios_withgrub` in the file name start with SeaBIOS
first, but also have GNU GRUB available in the boot menu when you press ESC.
### seabios\_grubfirst
### seabios\_grubfirst (DEFUNCT, WAS INTENDED ONLY FOR DESKTOPS)
ROM images that have `seabios_grubfirst` in the file name start with SeaBIOS,
but SeaBIOS is configured via special `bootorder` file in CBFS so as to ONLY
load GNU GRUB. This setup would be most useful on desktops, where you wish to
only have GNU GRUB available, but want to use an add-on GPU while also having
the option to use libgfxinit, if a supported GPU/framebuffer chip is present
on your board.
**DEFUNCT**
This build option is obsolete, and should not be used. It was deleted
in lbmk revision `e1bbdadc9584291cf062660d67128e9f17ab788e`.
It was believed, in earlier theory, that VGA ROM initialisation could
be used in SeaBIOS and then SeaBIOS boots into a GRUB payload (built
for coreboot), where the initialisation would continue to be used, but
it didn't work that way.
It's best to use PC GRUB (normal BIOS GRUB), but compile it into a floppy
image to insert inside CBFS, to then be executed by SeaBIOS. This is referred
to as SeaGRUB by the Libreboot project, and it would be quite useful
for desktop users, but it's largely irrelevant on laptops where
coreboot's own `libgfxinit` is usually available (or the option ROM is
easy to extract from vendor firmware and insert).
Where direct bare metal GRUB is desired, but you use a desktop system with
an add-on graphics card, you must extract the VGA ROM for your card and
insert it into the coreboot ROM, for coreboot itself to execute. This will
require custom configuration on your part, and it is thus beyond the scope
of the Libreboot project, in context of lbmk (automated build system).
Some older Libreboot releases included ROM images built using this option,
and those specific ROM images (`seabios_grubfirst` ones) should not be
used; you should only use `seabios_grubfirst` or `seabios`, in most
scenarios, if SeaBIOS is required.
For most desktop users, if running an external graphics card, it's easier
to simply boot in text mode with a SeaBIOS payload and use only that. This
will Just Work with almost all graphics cards, allowing you to use an
operating system with a full display and (drivers permitting) full 2D/3D
acceleration.
Which systems are supported?
============================