Re: U-Boot for Raspberry Pi

[Vagrant Cascadian]

On 2021-10-30, phodina via wrote:
> I'm trying to run Guix System on Raspberry Pi. In order to do that we
> need a way to boot it up.
>
> There is the nonfree Broadcom bootloader, which does the job and it's
> used by many distributions.
>
> However, there is also an open source alternative as U-Boot supports
> the BCM SoCs.

Well, you still need to load u-boot from the broadcom
firmware/bootloader...


> If I inherit from the u-boot itself and specify the name, it's then in the 
> list and I can build it.
> But the I can't use the package for the bootloader record.
>
> There must be something trivial I had overlooked.
>
> Could you please guide me on the procedure for porting the u-boot to new 
> board as a new Guix package?

There are install targets defined in gnu/bootloader/u-boot.scm, though
most (all?) of those targets install to a raw device offset, whereas
u-boot for the rpi needs u-boot.bin to be copied to your firmware
partition and needs to be specified as a "kernel" in config.txt, if I
recall correctly.


> (define-public u-boot-raspberry-pi-4
> (make-u-boot-package "rpi_4" "aarch64-linux-gnu"))

I would also try to keep the u-boot-BOARD matching the defconfig,
e.g. u-boot-rpi-4 instead of u-boot-raspberry-pi-4. Not for any
technical reason, per se, just keeping the u-boot target naming
consistent.

You might want to just build the u-boot package, and then manually copy
it to your firmware partition and configure that appropriately once, and
then just use guix to generate and update the extlinux.conf... I forget
the exact syntax to generate extlinux.conf without actually installing
u-boot, but I've done it in the past.

Another option would be to build the raspberry pi UEFI (not 100% sure of
the licensing, but reasonably free) instead of u-boot, and then use
guix's standard UEFI configuration with grub-efi and such.


live well,
  vagrant

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