[syslinux] How to chainload u-boot installed on the first partition with syslinux installed on another partition.

[Mario Marietto]

Did you understand my point ? I want to explain it as best as possible.
Let's take this tutorial as a base :

http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/

it does the following tasks :

1) it installs the unlocked u-boot custom version created by them on the
first partition
2) the script stores on the 3 partition two only files : uImage and exynos
5250-snow.dtb (and not :

d) config.5.18.1-stb-cbe+ : file
e) initrd.img-5.18.1-stb-cbe+ : file
f) System.map-5.18.1-stb-cbe+ : file
g) vmlinux.kpart-5.18.1-stb-cbe+ : file
h) zImage-5.18.1-stb.cbe+ : file

3) default bootstring is hardcoded there :

https://github.com/virtualopensystems/u-boot/blob/eecfeb578e296ef3b739ac918a39b6c177dff58a/include/configs/snow.h#L101

but :

#define CONFIG_EXTRA_ENV_SETTINGS \
EXYNOS_DEVICE_SETTINGS \
"dtaddr=0x43000000\0"\
"initrdaddr=0x44000000\0"\
"boot_noinitrd=mmc dev 1 ; mmc rescan 1 ; ext2load mmc 1:3 ${loadaddr}
uImage ; ext2load mmc 1:3 ${dtaddr} exynos5250-snow.dtb ; bootm ${loadaddr}
- ${dtaddr}\0"\
"boot_initrd=mmc dev 1 ; mmc rescan 1 ; ext2load mmc 1:3 ${loadaddr} uImage
; ext2load mmc 1:3 ${initrdaddr} initrd ; ext2load mmc 1:3 ${dtaddr}
exynos5250-snow.dtb ; bootm ${loadaddr} ${initrdaddr} ${dtaddr}\0"\
"bootdelay=3\0"

as you can see,it does not define any file like those shown above. I
mean,these files aren't hardcoded :

d) config.5.18.1-stb-cbe+ : file
e) initrd.img-5.18.1-stb-cbe+ : file
f) System.map-5.18.1-stb-cbe+ : file
g) vmlinux.kpart-5.18.1-stb-cbe+ : file
h) zImage-5.18.1-stb.cbe+ : file

so,my question is : if in both cases u-boot is used,how can I hardcode even
the missing files ? thanks.

Mario.

On Tue, Jul 4, 2023 at 2:55 AM Mario Marietto <marietto2008 at gmail.com>
wrote:

> u-boot can read these files ?
>
> d) config.5.18.1-stb-cbe+ : file
> e) initrd.img-5.18.1-stb-cbe+ : file
> f) System.map-5.18.1-stb-cbe+ : file
> g) vmlinux.kpart-5.18.1-stb-cbe+ : file
> h) zImage-5.18.1-stb.cbe+ : file
>
> i know that u-boot can read uImage file only, not config,initrd.img,
> system.map, vmlinux and zImage. which kind of modifications have been made
> to support rhis kind of files ?
>
> Il mar 4 lug 2023, 02:46 Adam Goldman <adamg at pobox.com> ha scritto:
>
>> On Tue, Jul 04, 2023 at 12:51:25AM +0200, Mario Marietto wrote:
>> > So,what's the bootloader used on those images ?
>>
>> It's U-boot. U-boot is reading extlinux.conf. Extlinux is not present
>> on those images. Extlinux does not run on ARM.
>>
>> -- Adam
>>
>

-- 
Mario.