Sometime back, my 3GS got upgraded to 6.0.1 from 4.3.3 (I swear without me confirming it?). Well, it ran slower and slower, so today I did a backup through itunes and let it upgrade to 6.1.3, but got the "There is no sim card installed" msg with my tmobile sim.

So I tried to follow the directions here Downgrade iPhone 3GS iOS 6.1 Baseband 5.16.08 to 5.13.04 for Unlocking | Beijing iPhone Repair using an old 4.1 ipsw I had saved.

Now I'm stuck with the phone wanting to connect to itunes. Tinyumbrella will try to kick it out, but it comes right back to the plug in to itunes screen.

Ideas? TIA