As instructed in the ChatBox when trying to help you…
Download the Patch Utility for Samsung drives: http://club.cdfreaks.com/f105/patch-utility-samsung-mtk-based-dvd-writers-v3-2-1-new-242508/
Download the stock SS01 firmware for your drive: http://codeguys.rpc1.org/firmwares/sony/dvdrw/stock/840A.SS01.stock.rar
Read up on how to flash a Samsung drive, and get SFDNWIN [if you actually read the thread, there is a link to it]: http://club.cdfreaks.com/f105/howto-flash-firmware-samsung-dvd-writer-231217/
Use the Patch Utility to patch your firmware so that it’s RPC1. Then flash following the instructions in the HOWTO that was linked above. Good luck.
And before you ask, your drive is a rebadged Samsung. I have done the process before on the drive.