This is a step by step guide on how to enable the Internet tethering option (which Apple wants us to have but AT&T is blocking) on a jailbroken iPhone running firmware 3.1.2.  Unlike other methods, this one will not break the visual voicemail feature.  These steps were created from some posts on redmondpie.com.

Step 1: Download CommCenter.patch for your iPhone 3G or iPhone 3GS.

Step 2: Move the downloaded CommCenter.patch file to your desktop.

Step 3: Make sure you have OpenSSH installed on your iPhone

  • Open Cydia. Touch on “Search” tab and then search for “OpenSSH”.

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

  • Install “OpenSSH” and reboot your iPhone.

Step 4: Connect your iPhone with your computer. Make sure iTunes is not running.

Step 5: Download and install Cyberduck for Mac. Enter the following details to login to your phone:

  • Server: The IP address of your iPhone. Settings –> WiFi –> <Your Network Name>
  • Username: root
  • Password: alpine
  • Protocol: SFTP (SSH File Transfer Protocol)

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

Step 6: Navigate to /System/Library/PrivateFrameworks/CoreTelephony.framework/Support/and copy “CommCenter” file to your desktop.

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

Step 7: Start Terminal and type the following command:

  • cd Desktop
  • bspatch CommCenter CommCenter-hacked CommCenter.patch

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

A new file named “CommCenter-hacked” should now be created on your desktop.

Step 8: Rename this “CommCenter-hacked” file on your desktop to CommCenter.

Step 9: Now copy this new CommCenter file back to your iPhone in the following location using Cyberduck:

/System/Library/PrivateFrameworks/CoreTelephony.framework/Support/

NOTE: Make a backup copy of the original CommCenter file on your iPhone so that you can restore to it in case something goes wrong.

Step 10: Now right-click on CommCenter file which you just copied, click on Info and change the permission to 755 as shown below.

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

Step 11: Restart your iPhone. Download and install the MobileConfig file by browsing to http://m.peacefulinsanity.com/Tether.mobileconfig from mobile Safari on your iPhone.

You should now have official Tethering option under Settings –> General –> Network.

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

Let me know if you have any questions or comments about this process.  If you would like tethering on your 2G iPhone, I would suggest you install the MyWi app on Cydia.