If it can be crossflashed, do the following:
Go here: http://dvdpro.club.st/firmware/BENQ_FW.htm
DL B7P9 or B7T9 .cvt files and cross flash it. Reboot or whatever.
Gohere. DL official FW like B7P9.
Go here: http://home.arcor.de/ala42
DL ala's great tool and unzip.
Then do this:
A. Load the FW that you DL'd into MCSE and click the increase read speed check box & hit Save.
B. Double click the speed patched FW and run the flasher while the drive is empty of media.
Enjoy your awesome BenQ1620, or as I've dubbed it elsewhere, the "RIPPING MONSTER."