Go to my firmware page and get :
1. How to use Lite-On Flash (IMPORTANT)
2. Lite-On Flash+.....
3. 1673S.JS07.16x.CROSSFLASHED.rar OR 1693S.KS04.16x.CROSSFLASHED.rar.
They both have been patched, READ SPEED=16x, Crossflashed, and recommended tweaks have been applied. Just extract and make sure to select the correct drive when flashing.
The 1673S can be crossflashed to a 1693S, so the choice is yours. The only difference is the 1693S CAN burn DVD-R DL.