Looks like folks at GadgetsDNA have found a way to update their iPhone 4 firmware to iOS 4.2.1 without upgrading its baseband version to 03.10.01. The update procedure involves editing your Windows/Mac HOSTS file, saving iOS 4.2.1 SHSH blobs using TinyUmbrella and restoring to iOS 4.2.1 directly from iTunes.
NOTE: We have not tested this method yet, so we do not recommend our visitors to try this method until they have factory unlocked iPhone 4. All those who rely on an unlocked device should wait for official PwnageTool update by iPhone Dev-Team or Sn0wbreeze tool by iH8sn0w
Steps to Edit HOSTS File on Windows:
- Open Notepad on Windows with administrator privileges. To do that, right-click on the Notepad icon and choose Run as administrator from the context-menu.
- Go to File->Open and browse to C:\Windows\System32\drivers\etc\ to open Windows HOSTS file.
- Now add the following line at the end of Windows HOSTS file as shown in the screenshot below:
- Press Ctrl+S to save HOSTS file.
Steps to Edit HOSTS File on Mac OS X:
- Click Go->Go to Folder and then enter path /etc
- Now open HOSTS file with TextEdit and add the following line with at the end of the file as shown in the screenshot below.
- Now go to File and choose Save As, uncheck If no extension is provide, use .txt and save the HOSTS file on your desktop.
- Now replace the original HOSTS file with the one you just saved on your desktop. Incase you are prompted for the password, just enter it and click OK.
Steps to Save iOS 4.1.2 SHSH Blobs with TinyUmbrella:
- Download and install TinyUmbrella on Windows or Mac OS X
- Plugin your iPhone to your PC with the USB cable and launch TinyUmbrella software.
- Select your iPhone from the side panel and click on the Save SHSH button. Wait while TinyUmbrella saves your SHSH blobs. Once your SHSH blobs are saved, you can see them under Saved SHSHs for <Your-Name>'s iPhone panel.
- Minimize TinyUmbrella (Do not start TSS Server)
Update iOS 4.2.1 on iPhone 4 from iTunes:
- Open iTunes and backup all of your iPhone data including photos, messages, apps and contacts etc.
- When iTunes will prompt to update the firmware of your device to iOS 4.2.1, click on Download and Update button.
- Now wait while iTunes updates your iPhone 4 to iOS 4.2.1. Once done, your iPhone will reboot into recovery mode and iTunes will throw 1013 error which indicates that your baseband has not been updated.
- Now open TinyUmbrella and click on the Exit Recovery button to kick your iPhone 4 out of recovery mode.
Jailbreak & Unlock iOS 4.2.1 on iPhone 4:
- Now you can jailbreak your iPhone using the latest version of Redsn0w tool. Click here for step-by-step instructions to jailbreak your iPhone 4 with Redsn0w 0.9.6b4.
- Once your iPhone has been jailbroken, you can unlock your iPhone using Ultrasn0w unlock tool. [via GadetsDNA]