How to unbrick/reflash Nexus S using stock ROM, stock tools I have a Nexus S that seems to have bricked itself.  I have never modded the ROM or phone, and it was totally stock. 

Now, it boots right int the white Google logo and stays there forever (I let it sit like this overnight and for many hours during the day, with several hard reboots.).  The only way to get the phone to reboot from this state is to pull the battery. 

I've downloaded the official Android SDK, and would like to reflash this phone back to a stock Google-provided ROM, using Google-provided tools. 

Everything I've found on the internet is for ClockworkMod, Cyanogen, etc.  I don't want to mod my phone, I just want to reflash a stock image using the "official" tools, but haven't been able to find instructions on where to get the images and how to do it.  

Any other help on how to unbrick this phone would be greatly appreciated.
You should try a factory reset before trying to reflash the phone.  AFAIK you need to unlock the bootloader (voiding your warranty) to flash a ROM, even on the Nexus S.

Instructions:


  
  Turn the power off. If your Nexus S is frozen, pull the battery out and reinsert it
  Hold the Volume Down button
  
  Press and release the Power button
  You are now presented with a menu that allows for Fastbook, Recovery, Clear Storage, and Simlock
  
  Select Clear Storage by pressing the Volume Down button
  Press and release the Power button
  Now simply confirm your decision: Volume Up for YES and Volume Down for NO