First make sure your drive is working 100%. Burn some disks and look if they play on your stand alone player. By flashing your drive you void waranty rules, so it's your own risk. When you want to flash your drive into a BenQ 1620pro, take a look at this page. http://dvdpro.club.st/firmware/BENQ_FW.htm
i would recommend to download the the firmware flasher (WinDW Flash.exe), firmware B7P9.cvt file and the original B7T9.exe file.
First flash the drive with the B7P9.cvt file using WinDWFlash.exe.
Restart computer after flash and than flash the drive with the original firmware B7T9. exe. Make sure that there is no media in the drive when you flash the firmware.
Important tip, do some reading first. you can flash your drive anytime. I only want to protect you for making dumb mistakes. Be patient take the time to know your drive.