Perhaps it could help any developer. My Iphone 4 was 5.0.1 and baseband 4.12.1 (the way it came to me in a different country). As there was no solution so i updated it to 6.01 IOS and baseband changed to 4.12.02.

As new untethered jailbreak is available so i did jailbreak. Now i was looking for unlocking as i was only using it as a ipod, i installed SAM pref and started playing with it. As usual no luck. I put new sim and it said invalid sim. then more activate deactivate through sam it turned to so service.
No i just found out that when i tried to call 112 it went through and in new country thats a invalid number so. Automated voice keep telling me you dialed a incorrect number.

How is that possible?

The iPhone is programmed to dial all emergency numbers across the globe without being activated. This means you can dial 112, 911, 999, etc. from any phone regardless of activation or unlock status. This should not be used as any sort of a valid test as to whether the phone is activated as all phones should successfully attempt to make these calls.

Beyond that, SAMPrefs is just an activation ticket manager -- not an unlock. It facilitates legitimate activation through iTunes servers for non-legitimate carriers, HOWEVER, it still requires you to utilize ultrasn0w in order to attain service on the non-legitimate carrier. If ultrasn0w cannot work on your baseband (which it cannot), SAMPrefs is not enough to unlock the phone.

Additionally, 04.12.02 is not unlockable with ultrasn0w. I do not believe there is a known way to downgrade to a unlockable baseband on that phone as Apple is no longer signing any of the exploitable basebands.