U-Boot: Difference between revisions

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~~'''~~U-Boot~~'''~~ is a common '''''platform firmware''''' implementation for embedded and embedded-like devices.

[https://www.u-boot.org/ U-Boot] is a common '''''platform firmware''''' implementation for embedded and embedded-like devices.

It may also be used as a bootloader, but with modern U-Boot, [[UEFI]] boot is generally possible too.

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</syntaxhighlight>

=== ~~Using~~ U-Boot ===

=== Installing U-Boot ===

You will need to consult either the [https://docs.u-boot.org/ Official U-Boot documentation], or a board-specific page to find out how to use the produced output.

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* [[NixOS on ARM]]

* [[NixOS on RISCV/VisionFive 2|NixOS on RISCV]]

== Using NixOS with U-Boot ==

With U-Boot, NixOS currently still assumes use of [https://docs.u-boot.org/en/v2024.04/develop/distro.html U-Boot's Generic Distro Configuration Concept] as the mechanism for discoverable boot. The preferred scheme is ''extlinux-compatible''. This is how the kernel <code>Image</code>, <code>initrd</code>, dtb, and Kernel command-line arguments are provided with complete support for the lifecycles of generations.

Note that U-Boot is moving to [https://docs.u-boot.org/en/v2024.04/develop/bootstd.html ''U-Boot Standard Boot'']. How it affects the assumptions from NixOS is still not documented.

Booting through UEFI with U-Boot should work. Booting with UEFI is tentatively supported, with intent of being the only fully supported boot method in the future. See [[NixOS on ARM/UEFI]], which describes part of the drawbacks.

=== Quick overview about the Generic Distro Configuration support ===

U-Boot is scripted to scan all attached storage devices and partitions, and look for a file named <code>/extlinux/extlinux.conf</code> or <code>/boot/extlinux/extlinux.conf</code>. This will will be generated by NixOS when configured with {{Nixos:option|boot.loader.generic-extlinux-compatible.enable}}.

The partition also needs to '''have its "bootable" flag set'''. This is true for ''both MBR and GPT partitioning schemes''.

== Vendor U-Boot ==

The term ''vendor U-Boot'' means the provided pre-built U-Boot binaries and the source as well. It generally implies use of an older fork of U-Boot from a ''BSP'' (''Board Support Package'').

Vendor U-Boot may or may not work to boot and use NixOS.

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* [https://source.denx.de/u-boot/u-boot Official U-Boot source repo]

* [https://docs.u-boot.org/ Official U-Boot documentation]

[[Category:Booting]]

@@ Line 1: / Line 1: @@
-'''U-Boot''' is a common '''''platform firmware''''' implementation for embedded and embedded-like devices.
+[https://www.u-boot.org/ U-Boot] is a common '''''platform firmware''''' implementation for embedded and embedded-like devices.
 It may also be used as a bootloader, but with modern U-Boot, [[UEFI]] boot is generally possible too.
@@ Line 59: / Line 59: @@
 </syntaxhighlight>
-=== Using U-Boot ===
+=== Installing U-Boot ===
 You will need to consult either the [https://docs.u-boot.org/ Official U-Boot documentation], or a board-specific page to find out how to use the produced output.
@@ Line 68: / Line 68: @@
 * [[NixOS on ARM]]
 * [[NixOS on RISCV/VisionFive 2|NixOS on RISCV]]
+== Using NixOS with U-Boot ==
+{{Note|This section assumes U-Boot is installed already.}}
+With U-Boot, NixOS currently still assumes use of [https://docs.u-boot.org/en/v2024.04/develop/distro.html U-Boot's Generic Distro Configuration Concept] as the mechanism for discoverable boot. The preferred scheme is ''extlinux-compatible''. This is how the kernel <code>Image</code>, <code>initrd</code>, dtb, and Kernel command-line arguments are provided with complete support for the lifecycles of generations.
+Note that U-Boot is moving to [https://docs.u-boot.org/en/v2024.04/develop/bootstd.html ''U-Boot Standard Boot'']. How it affects the assumptions from NixOS is still not documented.
+Booting through UEFI with U-Boot should work. Booting with UEFI is tentatively supported, with intent of being the only fully supported boot method in the future. See [[NixOS on ARM/UEFI]], which describes part of the drawbacks.
+=== Quick overview about the Generic Distro Configuration support ===
+U-Boot is scripted to scan all attached storage devices and partitions, and look for a file named <code>/extlinux/extlinux.conf</code> or <code>/boot/extlinux/extlinux.conf</code>. This will will be generated by NixOS when configured with {{Nixos:option|boot.loader.generic-extlinux-compatible.enable}}.
+The partition also needs to '''have its "bootable" flag set'''. This is true for ''both MBR and GPT partitioning schemes''.
 == Vendor U-Boot ==
+The term ''vendor U-Boot'' means the provided pre-built U-Boot binaries and the source as well. It generally implies use of an older fork of U-Boot from a ''BSP'' (''Board Support Package'').
 Vendor U-Boot may or may not work to boot and use NixOS.
@@ Line 92: / Line 108: @@
 * [https://source.denx.de/u-boot/u-boot Official U-Boot source repo]
 * [https://docs.u-boot.org/ Official U-Boot documentation]
+[[Category:Booting]]