Linux/PROCESSOR-SDK-AM335X: Run time modification of device tree

Hi
Thanks for reply .

In PSDK 5.00 (kernel 4.14) , DT overlay support supports runtime modification of device tree right ?

does DT overlay approach modifies kernel data structures for processing device tree at run time ? 
is there any TI document to understand it ?

can the patches for DT overlay features be provided so that I can patch 4.9 kernel with it and use this feature ?

Is it possible that the main dtb file is kept in a read only partition and the custom dtb file to overlaid be put in read write partition ?

for experiment , I tried using fdtput , I was able to modify dtb file at run time . however since the dtb file is kept in read only partition , this approach cannot work. moreover this approach edits dtb file which does not seems suitable.

One more thing , is the device tree overlay support present in u-boot ?