Official Android 4.0 for Nexus S tested on I9023

I own a GT-I9023 Nexus S phone. Google officially released 4.0 for Nexus s, so I immediately started to install it manually.
I downloaded the update from Google and installed it following this steps:

  • Copy to the root of your internal storage
  • Switch off your Nexus S
  • Hold Volume Up and Power to reboot into the bootloader
  • Select “Recovery,” then press power button
  • Once the triangle with exclamation mark appears, press power button and volume up at the same time to enter recovery menu
  • Select “Apply update from /sdcard”

At first I tought everything is OK, but then I noticed there is "No service", the phone could not connect to the mobile network, so no phone calls or mobile net access was available.
When I tried to figure out how to fix this, I realised that the recovery mode also become broken.
So... I was left with no working ROM and no recovery mode to install a working one...

I had to unlock the booloader and istall a custom recovery to fix this.

I installed Clockwork Recovery, you can find the instructions for this here:
CyanogenMod Wiki

I searched for this and the broken recovery seems to be a common issue with this update on I9023.

Hoewer being unable to connect to the mobile network, was a rare issue, but I was able find a promising tip.
I extracted the radio.img from a previous official rom, and flashed it separately on the 4.0, and it made the mobile network connection work!
flashing only the radio.img can be done using the fastboot tool with the command "fastboot flash radio radio.img"
To learn more about the fastboot tool see the link abowe about installing Clockwork Recovery.

At last everything seemed working, but after a few days I noticed that the battery drain become ridiculously fast, the phone is always awake, so the battery was completely drained with almost no usage in 17 hours.

This also seems to be a common issue, and Google have paused sending out OTA updates to "monitor feedback", so maybe they noticed there are a few problems with the update.

So the conclusion is to wait with the 4.0 update, beacause it seems to be have some basic issues.