No Image.gz-dtb after building kernel for Hikey970

I built Hikey970 kernel and then I expected to get Image.gz-dtb because Adnroid document for Hikey970 ( ) says “Copy the Image file (arch/arm64/boot/Image.gz-dtb) to the device/linaro/hikey-kernel directory as file: Image.gz-hikey970-4.9”.

But I couldn’t find Image.gz-dtb only I can see Image.gz. Please let me know how to get Image.gz-dtb for Hikey970.

I tried to use Image.gz for Image.gz-hikey970-4.9, built android won’t boot anymore.