I solved it. I must use proper dts file. So, to get everything work you need to make dtb file
dtc -I dts -O dtb -f sdm670.dts -o sdm670.dtb
and then append it to kernel
cat Image.gz sdm670.dtb > zImage.gz-dtb
and after that make boot.img and flash...
I have compiled kernel for sm-t725 device and flashed it from twrp. The bootloader is unlocked. After restarting the device it boots to twrp again. Then I choose boot to system and it does not boot.
I can't post photo, but it shows samsung label,...