[Yocto][i.mx8] How to add custom device tree to image?

[WolsYang]

Hi, I have a question: how to add a custom device tree to image?
I use yocto 3.4, and I add this line to my recipe.

linux-imx_%.bbappend

KERNEL_DEVICETREE += " freescale/imx8qxp-custom.dtb "

And it did make as dtb

/build$ ls tmp/deploy/images/imx8qxpc0mek | grep imx8qxp-custom.dtb
imx8qxp-custom.dtb

But not in my image, why？ Did I miss something?

switch to partitions #0, OK
mmc1 is current device
Failed to load 'boot.scr'
31062528 bytes read in 329 ms (90 MiB/s)
Booting from mmc ...
Failed to load 'imx8qxp-custom.dtb'
WARN: Cannot load the DT

[kl4m4]

I have tried the same thing in 3.4 but failed. Even fiddled with:

inherit kernel-devicetree

Because documentation says so. But the *.dtb file did not make it to final imx-boot image. What solved the problem was creating whole new machine, that was a copy of previously used machine, but with this one new dtb file mentioned in .conf file. For me this was preferred solution but it would be interesting to know why above approach did not work as expected.

Cheers!