If you have a Hitachi drive (shown on the left) Then you are basically out of luck because it cannot be flashed.
If you have a liteon drive than your drive can be flashed. However there are different versions of the liteon slim drive.
1.Liteon 9504
2.Liteon 0225
a-MXIC Chipset
b-Winbond Chipset- you will also need the Team Xecuter Liteon D6-16D4S Replacement PCB. The reason it requires the Liteon DG-16D4S Replacement PCB is because these drives have write-protect enabled on them, meaning you cannot write to these drives (without having to drill into the chipset, which can ruin the drive)

3.Liteon 0401- You will also need the Team Xecuter Liteon D6-16D4S Replacement PCB. The reason it requires the Liteon DG-16D4S Replacement PCB is because these drives also have write-protect enabled on them, meaning you cannot write to these drives (without having to drill into the chipset, which can ruin the drive)

If you have a 0225 the best way to find out wether its MXIC or Winbond chipset is by opening the drive and looking for the chipset.