How to Install CyanogenMod 9 ROM to Nexus S 4G

Koush’s CyanogenMod 9 release for the Nexus S (GSM) finally comes to the Nexus S 4G, thanks to members of Team Liberty (developers of the Liberty ROM) and other helpful programmers. In addition to getting the very same CyanogenMod 9 ROM for the Nexus S, users are treated to a few performance scripts, hacks, and tweaks (from the Liberty ROM) in the Nexus S 4G port.

The ROM seems to be in good working condition. According to the feedback from users, it runs smoothly and the operating system seems to run faster, although some users have reported occasional issues with GPS. Overall, the ROM seems okay for use daily.

If you’d like to install the CyanogenMod 9 port onto your Nexus S 4G, you’ll need a few things:

A rooted Nexus S 4G
ClockworkMod Recovery installed on your device
ICS AOSP ROM with Liberty Elements downloaded to your computer. Get the ROM here.
Make sure that your battery has a charge of at least 80% to prevent your device from shutting down in the middle of the update process.
Back up the data on your device so your data will be secure in the event the data gets lost or corrupted during the update process.
Enable USB Debugging. You can do so through “Settings > Applications > Development > USB Debugging”
Close all firewall and antivirus tools on your computer, as these may interrupt the update process.

Once you’ve got all the necessary tools and a backup made, you can now proceed to the installation process:

Connect your Nexus S 4G to the computer using a USB Cable.
Copy the ROM into the root of your SD card, without altering or unzipping the file.
Turn the device off.
Reboot the device into recovery mode.
Make a Nandroid backup.
Select “Wipe Data/Factory Reset”.
Select “Wipe Cache”.
Select “Wipe Dalvik Cache”.
Select “Install Zip from SD Card,” then “Choose Zip from SD Card”.
Select the ICS AOSP ROM with Liberty Elements file.
Once the file has been flashed, reboot your device.