CAUTION : iOS 4 jailbreak is way complicated unlike other jailbreaks. Please proceed with caution.
Requirements :

Jailbroken iPhone 3GS with older bootrom.
You haven’t used Spirit jailbreak before (for untethered jailbreak).
You have Windows (PC). For Mac, try Pwnage instead.
Please read the above requirements again.

More info about these custom firmware files :

[UPDATE] : You need to download files from either step 1a or 1b depending on your baseband preference. Both are unlockable, so I would go with step 1b which is the latest baseband which supposedly does better with the battery. step 1b …

UPDATE : A new version of custom firmware 3.1 for iPhone 2G/3G/3GS is now available here!
Free your iPhone 3G 3.0 from Apple’s chain by jailbreaking your iPhone which provides you with various customization features and even unlock feature which Apple and your official carrier hate! There are various options available to achieve this level of customization on your iPhone such as download firmware files, bootloader files, jailbreak/unlock tools such as Redsn0w/Pwnage or QuickPwn.

If you are not the one to download all the various files and just want the ultimate result, …

Those of you who want iPhone 3G 2.2.1 firmware with 2.28 Baseband and Cydia, download both the files below and join them using hj split.This works both on Windows and Mac. 2.2.1 may not be an important upgrade but it definitely puts and end to accidental upgrades to 2.30 baseband.

Please make sure your iPhone 3G is already pwned (you should have Cydia installed!).
Launch iTunes (Windows or Mac) and restore your iPhone to the downloaded Custom Firmware. (Hold Shift key (Windows) / Opt key (Mac) whle hitting the restore button in …

Once iNdependence v 1.4b5 was released with 1.1.4 support, I went ahead and updated the iPhone (16GB 1.1.3 OTB unlocked using iJailbreak)from 1.1.2 to 1.1.4 via iTunes which gave me an error. I repeated the same and the update went fine and now I have version 1.1.4 installed on the iPhone.
I then fired iNdependence trying to jailbreak/activate my iPhone. I hit the Activate button and it didn’t respond in a timely fashion showing me the Jailbreak screen. I then hit the Jailbreak tab to Jailbreak the iPhone which gave me …

UPDATE : Download ZiPhone Latest Release for Windows. A Mac version of the same can be had here.
ZiPhone GUI is built by i.unlock.no which is based on GeoHot’s unlock script which was generalized by Zibri 🙂 ZiPhoneGUI is for Windows users while Mac users have a better application in the form of iJailbreak. Talk about hackers/developers but yeah – they are the best! iPhone Devs have been keeping mum so far but hey, this method works the best!
Unlock option works with only 1.1.2 and 1.1.3 OTB iPhones and that makes …

Update : A much faster easier solution for Mac users can be found here. Windows users may resort to ZiPhoneGUI.
I am back after spending 4 hours on the entire process (which includes some hits and misses! Which means, you no longer have to figure out the right steps/combinations!!). Now the process is trimmed down to much lesser time and the best part being : No command line hackery!
All you need is an iPhone (OTB 1.1.2/1.1.3 BL 4.6), Mac (preferable) / Windows, Firmware files (1.1.2, 1.1.3 ipsws), courage to try this …

Well, now that 1.1.2 is released for quite some time now – why is the world not abuzz about upgrading to it? Mostly because – there is no reason to! Some say 1.1.2 sports better battery life while others say the iPhone performs faster (did it ever under perform?)!! For whatever reason, if you want to upgrade to the latest and still enjoy all the features (including unlock!!).Activating an iPhone 1.1.2 without iTunes is really a big deal because INdependence doesn’t support 1.1.2 yet and iDemocracy wasted some valuable …

Yeah, you heard it right! The best guide ever, just buy an iPhone from AAPL or ATT and sit there in the store and unlock it – the simplest it can ever get! You need WiFi btb!!No Mac or PC required! Unlock the iPhone straight out of the box! Save the money from investing in Unlocking software and use it wisely 😉
1. Slide for Emergency calls, dial *#307# press call, now use the back button on the top of your screen to remove *#307# , now enter 0 , …