UPDATE : A new version of custom firmware 3.1.2 for iPhone 2G/3G/3GS is now available here!

UPDATE : If you get a 1600 error while trying to restore to a custom firmware here, try this.

iPhone 2G and 3G users can now safely update to 3.1 firmware without updating the baseband (for unlock). If you are not the one to download all the various files and just want the ultimate result, these files are waiting for you to download! If you rather want to start from scratch, download Pwnage 3.1 tool for Mac.

• Caution #1 : Please proceed further only if you have an iPhone 2G/3G. iPhone 3GS files can be downloaded here.
• Caution #2 : A restore is going to wipe the iPhone clean. Hence, please backup your iPhone using iTunes and then proceed.

More info about these custom firmware files : Has factory boot logos (Apple and restore cable), Only Cydia, No Icy, Default root partition…

Step 1a) Download Files for iPhone 2G (Please read the following carefully)

• Download the following files ONLY if you have an Official iPhone contract with your cell carrier (ATT and others….)

iPhone 2G 3.1 Custom Firmware Not Activated Official Carriers Part 1

iPhone 2G 3.1 Custom Firmware Not Activated Official Carriers Part 2

OR

• Download the following files ONLY if you don’t have an iPhone contract (T-Mobile and others…)

iPhone 2G 3.1 Custom Firmware Activated for Other Carriers Part 1

iPhone 2G 3.1 Custom Firmware Activated for Other Carriers Part 2

Step 2) Join the downloaded files

• The files downloaded above have an extension .001 and .002. They need a special opensource (free) software HJSplit to join.

Download HJSplit to join both the files – Link for Windows Computers here and Macs here.

Step 3) Restore the firmware in iTunes 9.1

• You should now have the respective firmware file with an extension .ipsw . Please follow the steps in order.

Launch iTunes and connect the iPhone to your Mac / Windows computer.

If you are aware of DFU mode, proceed further. If not, watch this quick video and pay close attention to the steps to achieve DFU mode.

Turn your iPhone off. Press and hold the Home button and the Power button at the same time for 10 seconds.

After exactly 10 seconds release the Power button. Continue holding the Home button until iTunes pops up a message saying that it has detected an iPhone in recovery mode.

The iPhone will show you a blank screen (black).

Click on ‘Ok’ to the prompt displayed and hold Option key on your Mac and then hit Restore button. For Windows, hold the shift key and then hit the restore button. In the dialog box that pops up, browse the downloaded custom firmware file.

Step 4) Give it few minutes to perform the restore. Once the iPhone is up and running, proceed for software Unlock using Cydia. Follow this guide to install Ultrasn0w to software unlock your iPhone 3G. iPhone 2G is already unlocked with this custom firmware!

You are now good to go! Post a comment if you are stuck at any of the steps described above.

Related posts:

1. Download Custom Firmware 3.1.2 IPSW – Jailbreak, Activate, Unlock iPhone 2G, 3G, 3GS [Mac and Windows]
2. Download Custom iPhone 3G 3.0 Firmware ipsw Files to Activate, Jailbreak, Unlock iPhone 3G 3.0
3. Download Custom Firmware 3.1.3 IPSW – Jailbreak, Activate, Unlock iPhone 2G, 3G, 3GS [Mac + Windows]
4. Download Custom Firmware to Jailbreak and Unlock iPhone 3GS 3.1 [Mac/Windows]
5. Solution : Error 1600 while trying to Restore to Custome iPhone firmware for 2G / 3G iPhone Jailbreak