Thank you for your reply.
I’m definitely using devkit and I’ve only modified dtb and Image.
Maybe I worded it wrong, by custom kernel I meant the kernel I put together after removing GPIO usage in that device tree as per your advice Jetson Nano SPI Bus Not Working - #10 by KevinFFF and according to the instructions here Kernel Customization — Jetson Linux Developer Guide documentation. Then copied the created Image to /boot/arducam and /boot.
I agree with you that it is easier, before that I did it that way, but after changing the path to dtb in extlinux.conf:
LABEL JetsonIO
MENU LABEL Custom Header Config: <HDR40 User Custom [2023-05-24-170431]>
LINUX /boot/arducam/Image
FDT /boot/dtb/tegra210-p3448-0000-p3449-0000-b00-custom-kernel.dtb
it crashes quietly without any error message. I tried running this command again and I don’t even know how to show you that the console window flashes (for less than a second) while trying to open the utility (gray screen with a console frame), but immediately returns to the normal view.