I can tell you the HTC One M8 for Windows (Verizon Wireless) variant despite being unlocked for GSM, it didn't matter whether I used Straight Talk (AT&T) or a T-Mobile branded SIM card; it did not work...that said, this being an Android thread before I purchase a HTC One M8 Android - either an AT&T variant or Developer Edition variant, I wanted to double check with y'all as to whether like my HTC One M7 64GB DE if I also had to root and custom flash for example with ARHD 43.0 to enable the mobile network share aka wi-fi hotspot on the device? It works to perfection on my M7 with ARHD 92.0. (And before some jackass gets on here and tells did I search for this; yes, I did). Thanks everybody; take care and have a wonderful day!