At this thread you can find information about the released un-official firmware for NEC 6500A and related OEM drives.

A) The Basic Stuff

Q: Whats the purpose of those un-official firmware?
A: The main idea behind the un-official firmware is to offer additional "improvements" in terms of:

* RPC1: Region Free Drive
* Riplock: Removes 6X limit when ripping CSS DVD-Video discs
* ID: Change the ID of an official released firmware
* Media hacks: Change (usually increase) the writing speeds for specific DVD+/-R media

Q: I like the main idea, but why NEC doesn't offer the above features from box?
A: NEC as a member of the DVD-Forum must include RPC2 region protection for all DVD recorders. The Riplock is an additional measurement to prevent ripping that many companies have adopted, of course there is the official excuse that prevents noise/vibration when playback DVD-Video discs.

Q: Is it safe to use the un-official firmware?
A: Yes, you can go back to your original firmware anytime with the "correct" flasher.

Q: I see at many firmware the SE letters, what this mean?
A: Usually used to state the differences from the official firmware (SE=Special Edition)