If, OTOH, it does work at this point, then maybe test for interference with WiMAX; if so, they probably disabled it because they felt that rendered it useless, and we've got a cool hack with niche utility. If it seems unaffected, or no worse than WiFi, then it looks like a political issue, i.e. Sprint just didn't want people using their N810Ws as VoIPphones, and we are t3h liberators! (Not a conclusion I want to jump to prematurely, but a fairly obvious one if testing does turn out that way.)