I came across this while researching some specs for this unit, since I'm forced to rent this from At&t. Anyways, maybe someone can look over the code and possibly add some general fixes or features to address bufferbloat? (I'm not a programmer or else I would dig around!)
https://sourceforge.net/projects/nvg599.arris/files/NVG589-NVG599-11.6.0h0d48/
Incorrect reasoning?
... to vendor firmware? What could possibly be the motivation for that?
One thought that comes to mind is to "push" vendors in the right direction. I by no means have an affiliation to a vendor/entity to make changes, but even just evaluating the code could also gain some insight into the inner workings. This particular device is popular for distribution and could use some improvements. If the ISP won't fix it, maybe the vendor will if the appropriate discussions begin. Some positive thinking.