Howto customize linux kernel with BSP

I have a running Radxa rock-S0 with a cli debian and now I would like to customize the kernel.
I used BSP in my laptop and managed to create a first image with:
$ ./bsp linux stable

How can I cofigure the kernel, recompile and recreate the packages?
As a first try, I entered in the folder .src/linux/kernel and tried to run
make menuconfig

but It didnt work

Armbian allows you to customize the kernel, you can build your custom kernel (mainline-bsp, etc) packages using Armbian build system, you can give it a try.

@RadxaYuntian please give some advice

Once you are inside .src/linux you can use the standard Linux kernel configuration tool. You probably forgor to add ARCH=arm64 in your make command though.

Afterwards please first git fetch && git pull your bsp folder since there is some updates. Then you can run ./bsp linux stable --dirty to build without bsp resetting your code.

Please read more here.