So I'm back to the same problem. Seems like my unlock doesn't last longer then one day. Sooner or later all my signal bars go away, then I get a message saying that Network is No longer Available, and I get No Service where T-Mobile icon used to be. I remove my sim card, uninstall ultrasnow, hard reboot (home and power button). Then install ultrasnow again, hard reboot again. Then insert my sim and the phone works for no longer then a day, until I get the same problem.
I got iphone 3gs with 4.1 OS and 06.15 downgraded ipad firmware. What should I do? I'm trying to have my phone unlocked on T-Mobile. Should I try reinstalling custom 4.1 ipsw again or try going for 4.3.1? Seems like 4.2.1 option is no longer available through tinyumbrella.