Flashing KDZ you have to unlock bootloader again, root again, etc.

Easier way is to boot in twrp and then simply connect your phone to computer and use command "adb push" to copy rom zip to your phone's internal storage

Example; adb push C:\ROMS\theromv1.zip /data/media/
LG Optimus G E975
ROM:SAVVYROM V5.1

Asus Padfone 2 64gb Black
ROM:GuerillaROM-v1.3 OC version DEAD ATM

Sony Xperia S
ROM:eXistenZ Ultra 1.3.5

LG Optimus 4X HD
ROM:Zaiben RC7

Samsung Galaxy Gio
ROM:Reincarnation V.1.1