Jailbreaking the iPhone

Ok. So I finally succumbed to jailbreaking my iPhone. The main reason is being that I am now in Singapore, and the 'unlocked' iPhone I bought in India does not accept a SIM from singapore. What a stupid thing !

After a few days of carrying two phones, one which was actually 'unlocked' I decided to jailbreak the iPhone. As per a recent US Ruling, iPhone jailbreaking is legal.

Scouting around the web, the easiest way to jailbreak is to just browse to Jailbreakme.com. It shows a nice page with a "slide to unlock" . Ho ! this is going to be easy I thought. But just before doing the jailbreak, I thought about doing a backup... and thats when things went horribly wrong. So, this blog post is also an attempt for people who may face the same issues.

The adventure started with the update. I did not realize that a new iOS4 version ( 4.0.2) had come up, and without thinking I cliked 'update'.

Now, the 4.0.2 version from apple is a sneaky piece of software - it only blocks the jailbreak hack. So, ofcourse Jailbreakme.com did not work. Looked around on the web, and the only way forward was to downgrade the iphone.

Here is how you do a downgrade.

1. Download the relevant build. Go to this page to download the relevant firmware. Choose 4.0.1 (thats the latest as of now which can be jailbroken).
   
2. Start iTunes.
   
3. Connect your iPhone and select it.
   
4. You will see a button which says 'Restore'.
5. While pressing SHIFT click on Restore. This will prompt you which firmware version to restore to. Select the firmware you downloaded in 1 above.
   
6. The restore process takes some time. Go make some tea or something.
   
7. Once restored to 4.0.1 , navigate to Jailbreakme.com in the browser on the device. Slide to start the jailbreak process.
   
8. Jailbreak is just part of the process. What it does is opens up the iPhone to be able to install other 3rd party apps which is not part of the Apple Store - cause apple does not allow applications which messes with the system internals. The next step is to open up the SIM.
9. In point 8, one new app gets installed. Its called 'Cydia' which is an app store not controlled by Apple. Search for ultrasn0w in that. This is the SIM unlocking software. Install it.
   
10. Now you are good to go. Change the SIM to a local one.
    

Have fun now.

Issues etc.
One has issues with supported software, and here we are talking about unsupported software. So there are bound to be issues. Here are a few things that I faced.

1. For some firmware versions ( e.g. 3.1.3 ) you need to put the phone in the DFU (Device Firmgrade Upgrade) mode. If you are not able to get out of this mode after putting in the firmware, you will need RecBoot installed to get out of that mode.
   
2. Sometimes you get an error ( error code 10) during the downgrade portion. This will kind of leave your device in the hanging state ( happened to me). If this happens, disconnect the cable from the computer to the iPhone and use it on another USB port. Also make sure that the cable is the original iPhone one. I am using a different cable which was cheaper, but that causes problems.
   

Resources:
I did not dream up this process. The following sites were incredibly useful. Check them out:

• U.S. declares iPhone Jailbreaking Legal, over Apple's Objections : recent ruling in the USA makes it legal for users to jailbreak the iPhone.
  
• Rolling back your iPhone 3G to OS 3.1.3 : If you are not happy with the iOS4 as it really slows down the device, you may want to follow this guide to downgrade to 3.1.3. Just make sure that you download and install RecBoot before you begin the process as you are definitely going to need it.
  
• How to Downgrade Your iPhone 3G[S] from iOS4 to iOS 3.1.3 : Similar to the one above, but has a good video of how to get into the DFU mode.
  
• RecBoot : Download RecBoot from here.
• iPhone firmware files : List of all firmware restore files.
• How to Unlock the iPhone 4, 3GS, 3G using UltraSn0w.
• iOS jailbreaking : Wikipedia article on jailbreaking.