How to jailbreak iPhone 4G(ios4) using Limera1n:
Read every step carefully and apply them you will be able to jailbreak your iphone 4G or 3Gs
First you should look for your firmware(os) if it is ios4 than ok if you are running iphone 3G(firmware 3.13)or other than you should first install the latest firmware that is 4 or 4.01
here the link of firmware of ios(iphone 4)

then you should run dotnetfx35(.NET Framework 3.5) this software automatically…