I would change the SD shield slave select instead. Install the SD card on top of the NFC shield, first bending D10 just enough on the SD shield so it doesn't insert into the NFC shield, then install a jumper wire from D10 to D4.
I would change the SD shield slave select instead. Install the SD card on top of the NFC shield, first bending D10 just enough on the SD shield so it doesn't insert into the NFC shield, then install a jumper wire from D10 to D4.