Need to return your Nexus S back to T-Mobile your any other carrier for any reason? Well, you can unroot your Nexus S completely back to stock, very easy to do by following the step-by-step guide outlined here.
(For Nexus S 4G, please see How to Unroot Nexus S 4G.)
Step 1. Download the appropriate stock OTA zip file for your Nexus S.
Download this zip for i9020T and i9023 models:
Download this zip for i9020A:
Step 2. Copy the zip file to internal storage of your Nexus S.
Step 3. Power off your Nexus S then boot into bootloader by holding down both Volume Up and Power buttons. Choose “Recovery” and hit the Power button.
Step 4. You should be in ClockworkMod Recovery now, choose “install zip from sdcard” using Volume buttons then hit the Power button.
Step 5. Choose “choose zip from sdcard” then hit the Power button.
Step 6. Choose “i9020t_i9023.zip” OR “i9020a.zip” (depending on which file you copied over earlier) and hit the Power button.
Step 7. Choose “Yes” and hit the Power button.
Step 8. Your phone now should be updating itself with the stock OTA ROM.
Step 9. When install is complete, choose “Go Back” and hit Power button.
Step 10. Choose “Reboot system now” and hit the Power button to reboot.
Step 11. Turn off your Nexus S again and go back into bootloader by holding down Volume Up and Power button together. Then choose “recovery” and hit the Power button.
Step 12. Once you get the Android guy with exclamation mark, hit Volume Up and Power button at the same time until you get blue menus.
Step 13. Choose “wipe data/factory reset” and hit the Power button, this will erase all your personal data/apps/settings.
Step 14. Choose “Yes” and hit the Power button.
Step 15. Next, reboot your phone into bootloader by turning it off then holding down Volume Up and Power button together.
Step 16. Download fastboot.zip and unzip to your hard disk.
For Linux or Mac:
fastboot oem lock
./fastboot-mac oem lock
./fastboot-linux oem lock
You should see that the LOCK STATE on the Nexus S screen change from UNLOCKED to LOCKED.
That’s it, you’ve fully unrooted your Nexus S! Now, there might still be your files on the internal storage such as your photos, videos, and other personal files, just make sure you back them up before you return your phone.
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You will need a rooted Nexus S to install all ROM/kernels.
NOTE: PLEASE ONLY INSTALL ROMS INTENDED FOR YOUR VERSION OF Nexus S! Otherwise you WILL BRICK YOUR PHONE and I will not be responsible!
How to Root Nexus S!
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