If you are like me and you decide to give AT&T the middle finger and move away from U-Verse, there is still hope you can use the NVG510. It's uses are very limited however due to it's very poor engineering, even with root access.
It's fairly trivial to root and then disable the DHCP server, making it function as a dumb switch. From there, you can now configure it's wifi and such to be a dumb access point.
However, I did this and found the NVG510 is complete and utter crap. It has this really retarded power saving thing (power saving, yet it's still hot to the touch) which basically means "lets cut the wifi power to 1% after being on for 30 minutes"
So, in summary: how to recycle a U-Verse modem:
- Douse modem with gasoline
- Strike match
Actually though, I think I'm going to begin tinkering with the NVG510's internals. Maybe looking at trying to reflash it and doing other dangerous things... and when I inevitably brick it, proceed to those instructions.