This might come in handy for some people too:

I just this method many times to go back to stock, but the last time I tried this my device got into a bootloop. I actually fixed this by shutting down the phone, starting the phone with the power and volume down button pressed, releasing those buttons when the LG logo shows up and immediatly pressing them again, then choose to perform a factory reset. After the factory reset the phone booted like I expected it to. Might not work for everyone, but is defenitely worth a try before you try to flash the KDZ again.
Current phone
Model: LG L90 D405n
Recovery: TWRP
Rom: Quarx' CM11

Old phone: Sony Xperia E C1505 (Sold)
Recovery: TWRP and CWM combo
Rom: CM11 (Unstable nightly)

Old tablet: Asus Nexus 7 2013 (Broken)
Recovery: TWRP
Rom: CM11 (Official)

Samsung Galaxy Tab 3 7.0 (Sold)
Recovery: TWRP
Rom: RocketTab