I have a freshly recovered iPhone 3GS 6.1.6 via iTunes. My phone can't detect my sim card. I've already tried opening the phone and fixing the sim card slot. How can I activate it without a sim card?
Did you have it unlocked before using the iPad baseband? And then restored it to stock ios?
Sounds like your baseband is in inconsistent state and will not recognize any sims.
There is no hactivation tool for 6.1.6