In preparation for an iOS 4 Upgrade - Things To Do

If you have the following:-

- iPhone 3GS (Model MC)

- FW 3.1.2 / Baseband: 05.11.07

- Jailbreak with Spirit

- Old Bootroom (S/N: XX932XXXXXX means Week 32 Year 2009) Note: Newer Bootroom is week 40 and above)

However, Dev Team, have commented in their Forum the following statement:-

"iPhone 3GS

Summary: Currently, PwnageTool only works on previously jailbroken 3GS devices with the old bootrom.

• If you have a Jailbroken iPhone 3GS with the OLD BOOTROM and you DID NOT use Spirit to jailbreak then you can create the ipsw with PwnageTool 4.0 and restore with your jailbroken recovery mode.
• If you have an iPhone 3GS with the NEW BOOTROM this is NOT supported by PwnageTool 4.0 PwnageTool 4.01"

Since you have Jailbreak using Spirit and since there is no Spirit Jailbreak for iOS 4 yet, you have to do the following:-

1 - Restore back to 3.1.2 (Ensure SHSH is backup via Cydia)

2 - Jailbreak using Redsn0w. See --> HERE

3 - Jailbreak using Pwnage 4.0.1. See --> HERE

Update:

However, today, I realized I have not Jailbreak using Spirit but using a method called Blackra1n. If this is the case, I might be able to Jailbreak my 3.1.2 iPhone 3GS to iOS 4.

Just in case you have problem ... see this article --> Jailbreak and Unlock iPhone 3gS to iOS4 (also downgrade to lower firmwares) on Mac