In case you want to crossflash:
Simply find out, if the drive is in Master or in Slave configuration. Master is most common, but there are a few computers with opticals in Slave mode. So you need to make sure. Device manager can help. A drive in Master configuration is shown as device 0 (zero) on the respective controller. Slave should be device 1 then. There existed an older version of Nero Info Tool (IIRC 4.03) which gave that information graphically.
In case you flashed a firmware for the opposite operation mode, then you need an adapter to connect the drive to a desktop computer in order to flash the correct firmware. Not funny. Getting a replacement drive isn't fun either since drives with P-ATA interface are no longer available (with a few exceptions, mainly used drives).
Perhaps you leave the drive "as is", carefully cleaning the lens perhaps (no lens cleaner disc please) and using known-good blank media. Buying an external drive (one with own PSU) might be an option, too.
Also, you might search this Samsung Forum for 632D or L632D, there are a couple of threads which might be useful, even if they deal with drives from other OEMs like HP (own Compaq), Dell, etc.