LG G3 stuck in "Firnware Update" screen topic

I tried downgrading from stock lollipop to stock kitkat in order to be able to root the phone. I downloaded the correct .to-file and .dll-file and flashed the update with the LG flash tool. The update completed, and when the "Factory Reset 3" screen appeared i pulled the battery (followed a tutorial).

Now the phone won't boot. Whenever I try to boot it normally it goes right into the "Firmware Update" screen. I can't get it to boot normally, or even enter download mode. Any tips? Have I managed to hard brick it?