Re: agl-minimal-image not booting with uboot if dtoverlay=pwm is added to config.txt

[Jan-Simon Möller <dl9pf@xxxxxx>]

Am Donnerstag, 28. Juli 2022, 17:42:48 CEST schrieb Carles Sole via
lists.automotivelinux.org:
> Hello Jan-Simon,
>
> I was reviewing your reply once more and I managed to create a custom dtb
> called bcm2711-rpi-4-b+pwm.dtb. However I do not quite understand how do
> you tell u-boot to load your custom dtb instead of the original
> bcm2711-rpi-4-b.dtb. Can this be done a "permanent" way or do I need to go
> into the u-boot environment and load the dtb there?
>
> Any hints on this would be very much appreciated.

You need to tell the u-boot to pick it up. U-boot on the pi4 runs a script

bsp/meta-raspberrypi/recipes-bsp/rpi-u-boot-scr/rpi-u-boot-scr.bb
and
bsp/meta-raspberrypi/recipes-bsp/rpi-u-boot-scr/files/boot.cmd.in

essentially you need to replace this line:
fdt addr ${fdt_addr} && fdt get value bootargs /chosen bootargs

with something like:
fatload mmc 0:1 ${fdt_addr}  <name of the custom dtb file>
setenv bootargs "root=<insert root device here> console=ttyS0,115200n8 rw"

For inspiration, look at this job:
https://lava.automotivelinux.org/scheduler/job/27225#L325

It uses tftp instead of fatload, so you have to translate that a bit to a
local sdcard boot.


HTH.

Best,
Jan-Simon





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