Carrier Problem

[princeraiuk]

my iphone4 was working properly before with 4.0 Version, but when i update it with Version
4.2.1 (8C148) it's Carrier is Locked and i cannot make a call anymore now, it's working as ipod and in wi-fi network only, how can i make this iphone to start work with Carrier or Micro Sim? Please give me suggestions for Solution.

 

[Gregoris]

where did you buy the device from? sounds like it was jailbroken and unlocked to work with the carrier you where using but if you know what carrier its locked to maybe we can help you.. but the official baseband for 4.2.1 cant be unlocked so you would need to rely on hardware solutions