Raspberrypi dtb in /uboot /boot partitions


I’m using kirkstone mender release on rpi4. Everything runs fine. I started experimenting with kernel 6.6 on this release and it seems it runs fine. Just few things is that I’m cannot read cpu temp using sysfs only when copy dtb from /boot to /uboot. Does somebody know what is relation to dtbs in /uboot partition? When I remove dtbs from /uboot partition board cannot boot at all. Thanks.