I have a Teensy 4 connected to a Teensy Rev C audio shield. I've made the revised connections identified on the PJRC website to account for changed pins on the T4. I am able to run SamplePlayer successfully, but unable to get the T4 to communicate with a flash memory chip soldered onto the audio board or the SD card on the audio board.

Can someone please tell me all of the connections (T4 to audio board) that are needed for the T4 to communicate with the audio board flash memory and SD card.