Thanks for the file.
There is no MX25L640E on the schematic. However there are multiple SPI connections going to J6.
Is there another smaller board on the shield? Is the MX25L640E on that board? If yes, what is it?
Additionally, the SPI pins ( MOSI and SCK ) are routed trough the relay. That relay is controlled trough a pin connected to J9 (top right corner).
You need to find out:
- which of the SPI connections is the MX25L640E
- select the correct CS line (see schematic)
- check whether you need to pull the RELAY_CTRL high or low to the get relay into the right state for the connection to work.
-- I suspect you need to pull the pin high to enable the relay and therefore close the connection to connect your Arduino MOSI and SCK to the device/board on J6.
-- you can test whether the connection between COM1 and NO1 is closed or open when the board is not powered.