Iphone 4s shows carrier no signal bars

[Tenz007]

Hi there my iphone 4s shows the carrier (telecom Nz) but no signal bars. I cant ring or sms. I tried a firends sim, which is vodafone nz and i get full reception and phone works fine. My phone is factory unlocked so should be compatible with all carriers. Please help

 

[willerz2]

Do a full restore and see if that helps. If you're on iOS 5.X, re-restore using RedSn0w with SHSH blobs if you want to stay on iOS 5.X