[Q] JTAG and getting rid of 4.3 topic

Hello I was wondering if I could be pointed in the right direction. I was recently cursed with Samsung's knox crap because I didn't start messing with rooting until after the 4.3 update. Knox clicked and I am forever sick with 4.3. Except, I recently got a hold of a spare jtag connector from a friend. It is not a riff box it is an msp430-jtag connector. Would there be anyway way to hook this to my computer and write over 4.3 with an unlocked 4.3? Would I lose download mode or anything? I found a video of some guy decompiling 4.3 stock from a mini s4 and if you simply delete aboot.img sm1 sm2 and sm3 it fully gets rid of Knox. That is my goal with the jtag. Is there any software I can use that will read the storage? Well a jtag work in the first place or did Samsung find a way to prevent that too. Thanks!!!