You can already jailbreak iPhone 3GS iOS 4.1 with PwnageTool. It, however, is neither official version of PwnageTool nor is tested. So, follow at your own risk. Here is step by step guide to jailbreak iOS 4.1 on iPhone 3GS with unofficial PwnageTool:
Jailbreak iPhone 3GS (iOS 4.1) with PwnageTool
Downloads:
How-to Guide:
Step 1: Launch the modified PwnageTool and connect iPhone 3GS to your computer.
Step 2: Select Expert Mode / Advanced Mode and make sure your device is selected correctly (iPhone 3GS) and move ahead.
Step 3: In the next step, PwnageTool will attempt to select your firmware IPSW file automatically. If you have more than 1 IPSW files on your Mac then browse for the original iOS 4.1 firmware and select it. Then hit next.
Step 4: Customization options will appear, select “Global” and click next.
Step 5: In the next step, uncheck / deselect “Activate the iPhone” if you are not on official carrier and rely on unlock.
Step 6: Next you have to select iPhone partition size, keep it default (recommended) or change if you want to.
Step 7: (Optional) Now you’ll be selecting the repositories that you need. Repositories can later be managed in Cydia as well so you can skip this step.
Step 8: Now click “Create” and PwnageTool will start cooking custom iOS 4.1 IPSW for your iPhone 3GS. Specify a location and wait till the process completes.
Step 9: Now load custom IPSW in your iPhone using iTunes 10 and enjoy the iOS 4.1 jailbreak. If you need help on how to load custom IPSW proceed to step 10:
Step 10: Loading Custom IPSW: Launch iTunes 10, select your device from the sidebar, Mac: press and hold Alt key and click on “Restore”. (Important: Don’t click on “Update” or “Check for Updates”). Now browse for the custom IPSW that you just prepared with PwnageTool.
If loading IPSW doesn’t go well, try doing it in DFU mode.
Source: iSpazio
Thanks to Pete for correcting us. It’s for iPhone 3GS, not for 3G. We appologize for confusion.