I customized some folders in kernel_src.tbz2 (kernel, hardware folder) with getting from L4T version 32.6.1.
But I’d like to update manually these files into my jetson nano device that flashed with L4T version 32.3.1.
Can I do that? Is there any way to do this without creating a new image and reflashing my device?
It might or might not work. You’d have to start with the configuration you currently have in the 32.3.1, and then change configuration in a configuration editor (such as menuconfig or nconfig) starting at that configuration. In such a case you’d also have to install all modules. The device tree probably won’t need anything changed unless your edits to the kernel add or modify an existing driver that already uses the device tree.
This does not necessarily mention differences between cross compile and native compile, but will work with both:
I strongly recommend leaving the old kernel Image in place with its boot entry and adding a duplicate entry just before that in extlinux.conf; then edit to use “Image-modified” (or some similar name modification that leaves file “Image” unchanged). If CONFIG_LOCALVERSION is changed, then the old modules will be left alone and you can build modules and install them as a file copy (or tar, copy, unpack) in the new location. The configuration URL will explain how “uname -r” and module install location and CONFIG_LOCALVERSION are related.
Give it a try and find out if it works. Just leave the old entry, and assuming you have a serial console, then you’ll be able to pick the original boot entry if the new one fails.