importing custom SO file to AOSP

So the answer was quite simple. I really need to copy my lib to the system image, to the system/lib folder, because the make command doesn't copy it from out/target/product/generic/system/lib to system.img

the trick is to add this line

  PRODUCT_COPY_FILES += $(LOCAL_PATH)/my_lib.so:system/lib/my_lib.so

to full.mk file. it's location is: android-source/build/target/product also put the my_lib.so near it (as seen by the path)

if you are planning to run the image on a real device, add this line after the device name definition. f.ex. if you are running on Nexus 4, put it at android-source/device/lge/mako/full_mako.mk