I'm sorry if this is stupid / wrong way to go about thing but Is this possible ?
1) I update all the partitions except /system using flashtool.
2) since I have root, Mount /system on my phone as rw.
3) extract /system from the 4.3 ftf and push the entire content of system manually (keeping root in the process)
4) Reboot ?
Is this possible ?
I'm sure this procedure needs to be fine tuned as I'm sure the permissions of the files pushed might be wrong.
Any help / tips ?