Stuck at Firmware Update, can't enter download mode

Noob here, was simply trying to update from 4.4 to Lollipop using the LG PC Suite.

I thought it was supposed to be straightforward but it basically got stuck at the Firmware Update screen, 0% with a "B64" and ROOTED text in red below.

I've been trying to enter the other modes, holding volume + and power but it just keeps on going back to the same screen.

Any help appreciated.