THIS IS FOR I9020T ONLY! IF YOU DECIDE TO GET BRAVE AND TRY THIS ON AN I9020A, I9023 OR D720, MAY THE FORCE BE WITH YOU. I AM NOT RESPONSIBLE FOR ANY DAMAGE CAUSED TO ANY PHONE BY USING THIS ROM.
YOU MUST FLASH THIS ROM USING CLOCKWORKMOD RECOVERY. THIS WILL NOT FLASH USING THE STOCK ANDROID 3E RECOVERY AS THE ZIP FILE IS NOT SIGNED. I HAVE NOT TESTED IT ON OTHER RECOVERIES.
This is probably more for posterity now than anything else, however I have created a CWM-flashable full on ROM for the original Nexus S Gingerbread firmware, version 2.3, build GRH55. This is built exactly the same way that the full OTA ROM packages for 2.3.3 and 2.3.4 were built.
1. Since GRH55 did not include the script that automatically overwrites alternate recovery images with the stock one (this was introduced in GRH78/2.3.1), flashing this ZIP will flash the stock Android 3e recovery that came with GRH55. This means that ClockworkMod Recovery will go away after flashing this ZIP and you will need to re-flash it manually if you want it back.
2. Flashing this ZIP will overwrite your bootloader and radio, restoring them to I9020XXJK1 and I9020XXJK8 respectively. These are the versions that came stock with GRH55.
3. GRH55 is receiving OTA updates. As of this writing, the latest version of Android is 2.3.4, and Google is pushing an OTA update for 2.3 to 2.3.4.
4. This ZIP will NOT clear your user data or cache. For users running a stock ROM, I would highly suggest clearing your data and cache manually as sometimes downgrading without clearing data and cache can cause problems. If you are coming from a non-stock ROM, you are required to clear your data and cache or the ROM will not boot.
5. The market app works just fine but does not update to the current style and look. The market app that comes with GRH55 is version 2.12, which is the look that's now 2 generations old. For whatever reason, Google no longer allows version 2.12 to update to newer versions. That said, if you install a later version of the Android Market (3.0.27 as of this writing) manually, it will update to future versions automatically.
6. Since writing NFC tags wasn't introduced until GRI40/2.3.3, the Tags app is read-only.
7. There is no video chatting through Google Talk. This feature was not introduced until GRJ22/2.3.4.
1. Download the Stock GRH55 ROM package here.
2. Copy it to the root of your USB storage.
3. Reboot into ClockworkMod Recovery (or flash it).
4. Select "Install ZIP From SD Card"
5. Select "Choose ZIP"
6. Find the ZIP file and select it.
7. Wait for it to finish.
8. Wipe data and cache (optional but HIGHLY recommended for stock ROM users and REQUIRED for non-stock ROM users)
9. Reboot and have fun.