Can you unlock an iPhone with iFile or iFunbox?

I wanted to know if it is possible to unlock an iPhone using iFile or iFunbox by deleting or modding certain files. Specifically, I am using an iPhone 3G on jailbroken iOS 4.2.1.

No you need unlock it with ultrasnow, check the trusted unlock guide:
http://www.monitoring-softwares.com/how-to-unlock-iphone.html

Use ultrasnow.

No, you can not.

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