Hello @cyberhelmer ,
Thanks for your post.
I think you can refer to the user manual of frdm-mcxn947. It lists all the potential conflict for FlexIO and camera header.
Pins on J9 can technically be configured as GPIOs. However, if SmartDMA is actively using FlexIO for LCD, and J9 pins are shared with FlexIO or other active peripherals, then GPIO reads may fail due to bus contention or pin mux conflicts.
I recommend you check the pinmux in your project configuration, ensure J9 pins are not simultaneously assigned to FlexIO, CAN, I3C, or Ethernet. Also review and adjust solder jumpers if needed. You may disable SmartDMA temporarily and test GPIO reads from J9 to confirm they work independently.
Hope it helps.
BR
Celeste