I hope that you are aware, that as you changed some kernel build options from m to y, then you also need to clean current modules from your device:

rm /lib/modules/current

You cannot reuse any of the old modules in the filesystem, and you need to copy/install every module that you built into a new /lib/modules/current-directory, and this needs to be done _BEFORE_ you try to flash/boot to your new zImage, if you forgot that step, your kernel will _NEVER_ boot up. /lib/modules/current's modules need to match your kernel.

You can only reuse current /lib/modules/current if you only add new modules, but as your config file makes other changes, then old modules will conflict and stop booting.