Jetson Tx2 - Linux kernel modules, kernel issue

I am using Jetson Tx2, I flashed Jetson with Jetpack for very first time.
Then to load the Jetson with my custom built image, I was using tegra_defconfig->edited this. Removed CONFIG_BCMDHD and BCMDHD_PCIE options in defconfig, then created the .config file.

After building copied the Image to Jetson - /boot/Image. I expect that the bcmdhd, bcmdhd_pcie modules should NOT be there under /lib/modules/4.9.140-tegra/kernel/drivers/net/wireless.

But those modules are there.

second thing is, I tried install modules command (rootfs) and flashed the kernel, rootfs. After this the kernel did not boot.

How to remove the bcmdhd, bcmdhd_pcie modules? apart form making them =n in tegra_defconfig, do I need to do anything else?

Is installing modules is mandatory? not just Image building is enough.