So the AT&T HTC one enables you to disable LTE? You didn't have to root it and throw a different ROM on it? I was under the impression from what I have seen and read that AT&T disables selecting network speed on all devices except the Iphone. I too updated my Lumia 920 only to see it lose the field test menu. I was able to flash it back and will dismiss the update until I am confident that LTE is stable enough. I have the full bars and no data issue occasionally. I've seen it happen on ipads and iphones as well, but they are able to disable LTE. I've thought about switching carriers, but AT&T still has the best HSPA+ network. The problem is they don't want you to use it anymore. For now my phone is great, but at some point I will probably want to update it to keep up with the developments in the windows phone software. I am hoping LTE will be more reliable soon, or someone will figure out how get AT&T 920 to be able to select network speed again post-portico.