1) Download XFlash-X and LtnFW. Both can be found in the CD Freaks LiteOn forum's tool collection (it's a stickied post at the top)
2) Download the zipped firmware using the link provided.
3) Unzip. You should now have a .EXE file.
4) Run XFlash-X (use the GUI). Use it on the .EXE file you just unzipped. This should produce a .BIN file.
5) Run LtnFW. Select the update command, select the .BIN file that XFlash-X just created. MAKE SURE THAT YOU HAVE THE PROPER DRIVE SELECTED IN THE DROP DOWN MENU. And then flash. Be patient, as it will take a little while.