Apple iOS 4 final version isn’t officially released yet. That way iPhone Devteam also hold the release of official hacks to unlock and jailbreak iOS 4.0.
But however as unofficial tricks to jailbreak iOS 4 has been released (jailbreak iOS 4 using PwnageTool), a step-by-step guide also been leaked to unlock iOS 4.0 which is using Blacksn0w RC 2. Basically, the unofficial Blacksn0w RC2 released by Steve (developer of pushfix app) is patched version of Geohot’s unlock tool for iPhone 3.1.2.
7 Steps to Unlock iOS 4.0 Using Blacksn0w RC2 Final:
1. Firstly, Jailbreak iOS 4.0 on iPhone 3GS using PwnageTool.
2. Once you have jailbroken iPhone 3GS.0, use blacksn0w RC2 to unlock iOS 4.0.
3. Start Cydia app and Open Manage tabs
4. Now select sources and click on edit and then add, You will be prompted to enter url source, now type “http://cydia.pushfix.info” and click on [Add Source].
5. Once you have added source wait for Cydia to update packages
6. Now search for Blacksn0w and from the list click on “Blacksn0w RC2 Final” and click on Install.
7. Now just restart your iPhone and enjoy unlocked iOS 4.0, it may take about 80 seconds to boot & cell connection establishment on iPhone 3GS running iOS 4.0 unlocked with blacksn0w RC2 Final.
You could always get support from UnlockAlliPhone.com about any Unlock & JailBreak issue of any model of iPhone including iPhone 2G,3G & 3GS and also upcoming iPhone 4. They provide Premium Members Support for life time. Means just pay one time a small fee and you will receive support(real human support – avg response time 2 hour) for all present & future version of iPhone.
Source: Redmondpie , BlogsDNA
