Try use ramdisk without any modification, if it'll boot and wifi will not work on your old bootloader, then try use also wifi modules from 4.3 ramdisk (dhd.ko and another one , I don't remember name).
Try install towell root, then su from market, if it then allow install Apks then you will see all changes in the system and you can use important files.
Edit: also open SU apk and apply binary files, then are changes to see.
I tried just replacing the zimage file from 4.4.2 to 4.4.4 and also the whole split_img folder, black screen on both atempts[COLOR="Silver"]
---------- Post added at 06:28 PM ---------- Previous post was at 06:18 PM ----------
Just tried the 4.3 as well and it failed