[2G-3.1.3] Just recieved?

I just recieved a 2G (8G) iPhone with 3.1.3 OS from overseas. Informations as I see from settings -> about are as follows:

version: 3.1.3 (7E18)
Carrier: SFR 5.1
Model: MB489FB
IMEI: 01 180800 0626542
IC CID
modem firmware: 05.12.01

It is already jailbroken but can't make any call with it in Iran. No locked sign and WIFI and youtube are working fine. How can I fix it. When I making calls it says "call failed"?

It also shows "invalid sim" for a second when I insert sim inside but after that it indicates signal sign but no carrier. It seems I have to change the carrier but there is no "carrier" option in the settings to choose from or do auto search. What should I do now?


:(

It's a 3G phone

No unlock exists for that baseband.

OK now I saw small "lock" at the top when the phone is in battery charging state. But I though only 3Gs can't be unlocked. If it is 3G there should be an unlock procedure?

Bytheway where it shows it is 3G?

it is the baseband 05.12.01 that cannot be unlocked.