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 2x
ROM:tonyp CM10 "Look ma! No Hands"
HTC Sensation XL
ROM:[runnymede] PAC-man VERSION 2