restoring firmware

Can't downgrade bb so just stay on the firmware you are on now until an unlock which should be out in around a month. If you bought a 3G like me on or around when they first came out you can downgrade the bb. Search fuzzy band in cydia, install it, and it will tell you if you can. If you can't just stay on your current firmware.

 

Upgrading to 4.1 firmware also upgrades the baseband to 5.14. Currently, that baseband can't be unlock to use with different carriers, like T-Mobile. If the 3G iPhone has 5.08 bootloader, there is hope.

iH8sn0w.com | Jailbreak your iPod touches and iPhones
Use F0recast (link ^^^) and see if you have 5.08 bootloader =>use Fuzzyband to downgrade to unlockable baseband.

If you do, JB with Redsn0w which adds Cydia. In Cydia, install Fuzzyband to downgrade the baseband, and then, install Ultrasn0w to unlock so you can use it with T-mobile.

If you don't, you will need to wait for possible 5.14 baseband unlock. As to when, nobody knows. Latest rumor is shortly after 4.2 firmware is released.

 

You're sol for now. Your husband did a good one this time
You cannot unlock just jb it and use it only with AT&T sims.