Gevey sim will not work kwenye iphone 4/4s especially on ios 6.0.1+....unless you preseved modemfirmware baseband from old 5.0.1.
The only way is to remote unlock or buy unlock code which depends on your imei and network carrier (o2)which from the internet for o2 network is $100-120.
Wote watakuzungusha mpaka utakoma..