In all of the LiteOns I've flashed, I've always been under the impression that you could not flash the OFW back onto the drive - that once flashed, it stayed flashed.
However there seems to be some LiteOn OFW with the new LT firmware. I've not tried it nor have I heard any mention of it in most forums I skulk around, but it may let you flash LiteOns back to OFW.