An email regarding this was only very vaguely answered, but what I read from it and the legal agreement you accept regarding warranty (from the BenQ site) was:
- using a third party flasher is considered unauthorized maintenance by BenQ
- you have no "license" to use BenQ firmware on your bulk drive
Whether this would void warranty they refused to tell me. I would think they wont find out if you did it. But legally, everything but using a program BenQ releases via their website for your specific drive is unauthorized servicing. Only official patches/updates are considered legal user servicing. Now guess why the B firmware upgraders do not upgrade your G fw drive?
Some people told about DW1620 bulk -> DW1600 -> DW1620 retail. I am not sure about this, but as your drive is no DW1600, the first step would be ... unauthorized servicing again, probably.
I think this sucks ... but common sense or logical conclusions are not necessarily consistent with legal matters.
If someone were able to get a real answer from BenQ regarding this it would be great if he could post it here. The German/European BenQ service is a POS only and the people sitting there dont know sh!t from chocolade. Sorry to have to say that.