5.4.1  Kernel config
Once the kernel has built you can check the kernel config. You can use the Mer kernel config checker:
HABUILD_SDK $
cd $ANDROID_ROOT
hybris/mer-kernel-check/mer_verify_kernel_config \
./out/target/product/$DEVICE/obj/KERNEL_OBJ/.config
Apply listed modifications to the defconfig file that CM is using. Which one? It’s different for every device, most
likely first:
•  Check the value of
TARGET_KERNEL_CONFIG
under $ANDROID_ROOT/device/$VENDOR/*/BoardConfig*.mk
•  Examine the output of
make bootimage
for which defconfig is taken when you’re building kernel,  e.g.:
make -C kernel/lge/hammerhead ... cyanogenmod_hammerhead_defconfig
•  Check CM kernel’s commit history of the
arch/arm/configs
folder, look for defconfig
If you are in a rush, get rid only of
ERROR
cases first, but don’t forget to come back to the
WARNING
ones too.
After you’ll have applied the needed changes, re-run
make hybris-boot
and re-verify.  Lather, rinse, repeat
:) Run also
make hybris-recovery
in the end when no more errors