In one post of yours I read that the burner's memory consists of three parts: 1. the safe mode firmware, 2. the actual firmware that gets exchanged by flashing new firmware and 3. a part where the serial number etc. and settings are stored, and I guess the booktype settings, too, plus its counter of changes.
So now you made me curious about those older NEC drives, how does the HP firmware for those two 1/2xxx drives alter the settings in the drives ROM so that it's irreversibly changed? I mean, wouldn't it be possible to flash the drive with another firmware that resets those changes? What I'm asking is: was there simply no patched or unpatched firmware around that could have reset those changes because noone bothered to make one (since using modded firmware is accompanied with a voluntarily void of warranty) or was it just impossible to revert those changes?
In other words and as a general technical question about DVD burners: Is there a part in those drive's memory that can only be written once? Either like a counter (e.g. number of firmware flashings, discs written) or other code (like additional manufacturer IDs or drive commands)?
If that's the case I can really understand why DVD-RW manufacturers don't want to RMA modded drives that were "messed" around with...