Thanks for posting the issue with internet sharing
Here's the fix
Use reg edit and change these values:
HKCU\SOFTWARE\MICROSOFT\INTERNETSHARING\LASTCELLCA LL CHANGE TO "MEdia Net"
HKLM\Comm\InternetSharing\ForceCellConnection change to "MEdia Net"
AT&T blocked option to change connection type so you have to change that in reg.
Now just softreset and enjoy.
I'm using it right now