So I tried returning my Sprint LG G3 back to stock using the LG Flash Tool. Somewhere near the end of the unrooting process, there was an error on the Flashtool, saying "USB OPEN PORT FAIL!" On my G3, there was a blue screen saying "Factory Reset Status" and a big, red 2. Many people have suggested switching to Board DL on the Flashtool, but there's one more problem. I can't enter download mode! I can, however, boot into Recovery Mode just fine, but I can't get into Download Mode no matter what I do. Can anybody help? Thanks!