Aw: Re: Re: Re: barebox extending boot-scripts

Frank Wunderlich frank-w at
Fri Jan 7 08:42:22 PST 2022


missed the defaultenv_append_directory(defaultenv_rk3568); in board-file...after adding that it seems to work

> Gesendet: Freitag, 07. Januar 2022 um 14:07 Uhr
> Von: "Sascha Hauer" <sha at>
> Yes. Furthermore you have to add to the board code:
> 	defaultenv_append_directory(defaultenv_rk3568);

maybe this is the part i've missed. i thought it were 2 ways...either link via makefile or add to boards code

> > > > > Boot scripts for publicly available evaluation kits are often not good candidates
> > > > > for upstreaming, because everybody using the EVKs has different thoughts on how to
> > > > > boot. The best way would be to use bootloader spec. It's one or more files you
> > > > > place at a known location that describe where your kernel and device tree are and
> > > > > what command line arguments to use and barebox can then automatically generate
> > > > > boot entries from all available bootloader spec files.
> >
> > is extlinux (i used in uboot and conf-file is already present) supported here?
> >
> > > > > See for an example
> > > > > of how to set this up. This is what I'd recommend instead of writing your own
> > > > > scripts.
> >
> > i do not fully understand the bootloader spec in the pdf as config file seems to be
> >
> > /mnt/mmc0.4/loader/entries/stm32mp157c-dk2.conf
> >
> > and then
> > boot -d mmc0.4
> >
> > is the path (loader/entries) seems to be fixed and all files there will be processed (which order)?
> Yes. No particular order, I guess it would be the order it is on the
> filesystem.
> > how is root appended (/dev/mmcblkXpY|uuid|...) when linux-appendroot is set to true?
> When root is appended it is assumed to be the same fs that also has the
> bootloader spec file, so the rootfs also has the entry and the kernel.

ok, then this is not usable for me, as i have a boot-partition (bootloader+kernel+dtb) and separate rootfs-partition

> > this is for testing multiple kernels with changing filenames (very
> > dynamic process, e.g. using 1 kernel binary with multiple dtb) and to
> > avoid adding a bootmenu entry everytime....this is not for end-user :)
> In that case you could also use bootm directly.

yes but my approach is to list the available kernels before and ask to enter the filename to not everytime look for correct commands ;)

> > and here scripting is imho the best way...this allows me to add extra
> > params to cmdline too (like debug level,dumping offsets) without
> > changing a distroboot config
> Not sure if you know already, but barebox concatenates all variables in
> the "global.linux.bootargs." namespace to the kernel command line, so
> you can easily add or remove a variable to add/remove kernel options
> without affecting unrelated options.

i know some options from documentation like this i've used to get a earlycon for tftp

global linux.bootargs.debug="earlycon=uart8250,mmio32,0xfe660000 earlyprintk"

> > for fixed kernels i have defined an extlinux.conf for uboot, but i'm
> > unsure if barebox can use this file too. have not found anything about
> > extlinux/syslinux in barebox yet.
> No, not yet.

ok, i created a bootloader-config like described in the pdf:

cat /mnt/sd.1/loader/entries/linux-gz.conf
title Linux GZip
version 5.16
options earlycon=uart8250,mmio32,0xfe660000 console=ttyS2,1500000n8
linux /extlinux/Image_5.16.gz
devicetree /extlinux/dtb_5.16
initrd /rootfs.cpio.lz4

but on starting it is skipped due to devicetree mismatch

boot -d sd.1
blspec: ignoring entry with incompatible devicetree "rockchip,rk3568-bpi-r2pro"
blspec: ignoring entry with incompatible devicetree "rockchip,rk3568-bpi-r2pro"
Nothing bootable found on 'sd.1'
Nothing bootable found

in barebox i use the evb whereas in linux i already have a separate dts. Can i override the compatible for the bootloader or do i need to add my board (as copy of evb first)?

btw. don't you get my direct messages (regarding vop2 driver for rk3568 and the result of my barebox environment-tests)?

regards Frank

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