Nano + Custom Carrier board, GPIO4 cannot be set to input

We have custom carrier board and I have tried following instruction from Updating Bootloader Pinmux in Platform… Bring-up. Please verify instruction on step 5 below.
Copy the generated .dtsi files from the directory that contains the spreadsheet to the following locations:
jetson_nano_module-pinmux.dtsi to <src_path>/hardware/nvidia/platform/t210/porg/kernel-dts/porg-
jetson_nano_module-gpio.dtsi to <src_path>/hardware/nvidia/platform/t210/porg/kernel-dts/porg-

I have tegra210-p3448-0002-p3449-0000-b00.dts by following the step 3. After flashed Production SOM and run "echo 65 > /sys/class/gpio/export, " it said …busy… It seems that Pinmux files did not update. Also, gpio4 is configured in tegr210-prog-p3448-common.dtsi.

You can check the gpio pins from /sys/kernel/debug/gpio. The reason of saying busy might be that you have set this pin already.

hello nielbuss,

you should also disassembler the dtb file into text file for examination.
for example, $ dtc -I dtb -O dts -o output.txt tegra210.dtb