ASUS Tinker Board custom kernel will not boot

Hello,

I want to compile a custom kernel with overlayfs support for ASUS Tinker Board but it simply would not boot. I installed DietPI and am trying to replace its kernel.

The kernel I am using:
https://github.com/TinkerBoard/debian_kernel

The commands I use to compile kernel:

make rockchip_linux_defconfig

# Here I enable Overlayfs support, I also disable networking support because otherwise it does not compile
make menuconfig

make -j8 zImage modules rk3288-miniarm.dtb

After I do that I get zImage and device tree, I mount the boot partition of SD card and copy zImage and device tree there. When I give the board power it starts off with the red light on (which should be ok), then the red light stops and the green one has a short blink and only darkness after.

What could I be doing wrong? How does u-boot load the kernel on ASUS Tinker Board?

Thank you!

Now I built zImage from Armbian source and I at least get some output on HDMI, but unfortunatelly only errors. It looks like the kernel starts but does not load filesystem or something.

I get the following kernel panic:

kernel panic-not syncing: VFS: unable to mount root fs on unknown block(0,0)

Here is an image of the screen I get:
https://i.imgur.com/mkV0jiy.jpg

How do I tell the kernel to use my initramfs?