Downgrade Nexus S from 4.0 to 2.3

Android 4.1 might too heavy for Nexus S hardware, below is howto downgrade the rom to ver 2.3.

Please note that all data on the phone will erase....

1. Download the image from google site.

2. Extract the file....

$cd /tmp/

$ tar -zxvf soju-grk39f-factory-5ab09c98.tgz
soju-grk39f/
soju-grk39f/bootloader-crespo-i9020xxka3.img
soju-grk39f/flash-base.sh
soju-grk39f/image-soju-grk39f.zip
soju-grk39f/radio-crespo-i9020xxkf1.img
soju-grk39f/flash-all.sh

3. Switch off  the phone, holding the vol up & power button at the same time until you see the bootloader screen.

4. Assume you have android-sdk installed, if not please refer to http://developer.android.com/sdk/installing/index.html for installation.

$cd soju-grk39f

$ ./flash-all.sh 

sending 'bootloader' (1536 KB)...

OKAY [  0.226s]

writing 'bootloader'...

OKAY [  0.344s]

finished. total time: 0.570s

rebooting into bootloader...

OKAY [  0.001s]

finished. total time: 0.001s

sending 'radio' (12288 KB)...

OKAY [  1.803s]

writing 'radio'...

OKAY [  1.680s]

finished. total time: 3.483s

rebooting into bootloader...

OKAY [  0.001s]

finished. total time: 0.001s

archive does not contain 'boot.sig'

archive does not contain 'recovery.sig'

archive does not contain 'system.sig'

--------------------------------------------

Bootloader Version...: I9020XXKA3

Baseband Version.....: I9020XXKF1

Serial Number........: 363003C175D100EC

--------------------------------------------

checking product...

OKAY [  0.001s]

checking version-bootloader...

OKAY [  0.001s]

checking version-baseband...

OKAY [  0.001s]

sending 'boot' (2936 KB)...

OKAY [  0.417s]

writing 'boot'...

OKAY [  0.383s]

sending 'recovery' (3176 KB)...

OKAY [  0.459s]

writing 'recovery'...

OKAY [  0.411s]

sending 'system' (188235 KB)...

OKAY [ 27.062s]

writing 'system'...

OKAY [ 23.307s]

erasing 'userdata'...

OKAY [  0.203s]

formatting 'userdata' partition...

Erase successful, but not automatically formatting.

Can't determine partition type.

OKAY [  0.001s]

erasing 'cache'...

OKAY [  2.017s]

formatting 'cache' partition...

Erase successful, but not automatically formatting.

Can't determine partition type.

OKAY [  0.001s]

rebooting...

finished. total time: 54.268s

DONE....