P4 1.5GHz CPU
256MB mem
Asus P4B i845 mbd
Win XP SP2
Lite-On SOHW-812S burner
BenQ DW1620.0C3 burner

I am a DVD newbie looking for help. The BenQ came with FW:

G7L9

I didn't test it with this or have the software to save a copy. I had no problems with my Lite-On, so I just went to:

http://dvdpro.club.st/firmware/BENQ_FW.htm

and flashed it with:

G7Z9RPC1

Without testing it, I installed it in a friends system as a slave on the primary IDE. Inserting a blank disk caused the system to reboot.
I re-installed it in my system and got the same behaviour. Moving the drive to the seconday IDE stopped the reboots. However, neither Win nor Nero would recognize that there was a disk in the drive. The Lite-On had no problem with the same disk.
I tried flashing it with:

G7M9, G7M9RPC1, G7T9, G7K9

and had various problems. When I could get Nero to burn an image to disk, the system rebooted when Nero completed.
The only time I got stable behaviour was with:

G7Z9

but, obviously, I was trying to make the drive region free. Any suggestions?

PS: During one of the tests I got an error and now one of my 4x Nexxtech DVD-RW disks isn't recognized by Win or Nero in either drive. Is there a utlitly which can recover this disk or is it a coaster now?

G7Z9 is not he latest OEM firmware in fact its one of the oldest (but yes I can see how you could make that mistake as it goes against BenQ's firmware naming scheme) you'll want to use G7V9 which is the most recent.

I suggest replacing the IDE cable that your using and set the drive as the secondary master, plus if your using an nForce motherboard and have its IDE drivers installed un-install them by going into the device manager and bring up the properties for the IDE controllers and click on the roll back driver that will bring them back to the Microsoft drivers.

As for the Nexxtech well sometimes when a RW is no longer recognisable by another drive usually erasing it in another sometimes works but if it didn’t work in the Lite-On either then you might be put of luck I'd say it’s not worth the trouble go get a Verbatim RW disc instead.

As for making it region free try AnyDVD otherwise you'll have to make do with any RPC1 firmware’s that are out their for the OEM Gxxx line. You could cross flash it to the retail Bxxx series and use their RPC1 firmware’s but doing so invalidates your warranty.