custom hardware and overlay files

[Tron]

In order to compile against custom hardware, we changed overlay and dts files, but I cannot remember which. How do I find out?

I get the error 

devicetree error: 'ss-pin' appears in /soc/peripheral@40000000/spi@b000 in nrf9160_pca10090ns.dts.pre.tmp, but is not declared in 'properties:' in C:/nrfTest-1.1/ncs/zephyr/dts/bindings\spi\nordic,nrf-spim.yaml
CMake Error at C:/nrfTest-1.1/ncs/zephyr/cmake/dts.cmake:182 (message):
new extractor failed with return code: 1
Call Stack (most recent call first):
C:/nrfTest-1.1/ncs/zephyr/cmake/app/boilerplate.cmake:566 (include)
CMakeLists.txt:9 (include)

[Tron]

For my custom board, I had to remove the  'compatible = "nordic,nrf-twim";' line from the dts overlay common file in order to make it work.