On Sunday afternoon, I finally got around to upgrading my jail-broken first-generation iPhone to the version 2.0 firmware. Previously, it was running 1.1.4, unlocked with ZiPhone.

Overall, apart from forgetting to back up my contacts before I did the factory restore, the whole upgrade process was much easier than I expected. Here’s how I did it, using my Powerbook G4.

What you’ll need:

• The latest version of iTunes.
• The version 2.0 firmware update: iPhone1,1_2.0_5A347_Restore.ipsw (218MB).
• PwnageTool 2.0 (19MB).
• A cable to plug your iPhone into your Mac.

Let’s get started.

1. Plug your iPhone in and back up everything you want to keep.
2. Reset your iPhone to factory defaults. In iTunes, hold down Option and click Restore. Select the iPhone1,1_2.0_5A347_Restore.ipsw file you downloaded before. It will take a few minutes to restore.
3. When the restore is complete and your phone has turned back on again, open up PwnageTool. Set the device to iPhone and enable Expert Mode. Load the same iPhone1,1_2.0_5A347_Restore.ipsw file from before.
4. When prompted, disable the stupid pineapple and Steve Jobs logos. Everything else I left at default settings.
5. Complete the Pwnage process and follow any onscreen instructions (e.g. entering DFU mode). It will generate a patched IPSW file which will be used to load onto the phone.
6. Return to iTunes, hold Option and click Restore again. This time select the custom IPSW file that was created by PwnageTool.
7. When it finishes restoring, your iPhone will restart and do some BootNeuter stuff. After that, it should be back up and running with version 2.0 of the operating system.

If you’re using the Vodafone New Zealand network, iTunes will prompt you to download and install a new carrier bundle. If you don’t have an iPhone data plan, this will break your default APN, and GPRS data will stop working. To fix this, browse to unlockit.co.nz on your iPhone and click the “Allow Data on any SIM” link.