how to unlock a jailbroken iphone 3gs

[brishearer]

I have an I phone 3GS 16MB. Apparently it is "Jailbroken" (whatever that means). my grandson tried to upgrade it from 4.1? to 6.1.3 and when he connected it to I tunes it jammed the phone which now says " there is no SIM card in the phone" (there is) and now I cannot use the phone at all. Would appreciate some help please.

 

[te100]

In essence, jailbreaking your iPhone means freeing it from the limitations imposed on it by your carrier, whether that's AT&T or Verizon, and Apple. You install a software application on your computer, and then transfer it to your iPhone, where it "breaks open" the iPhone’s file system to allow you to modify it.

That being said I think you will have to restore it to original. Your carrier will not help and void your warranty if you jailbreak it.