Nexus One owners who are running their device over Android 2.3.4 GRJ22, and still waiting for Android 2.3.6 Gingerbread (GRK39F) OTA can follow the guide below to flash the latest update to their device manually.
Note: It is not confirmed either it works for rooted Nexus One or not
Warning: We are not responsible for any damage to your device by following given process below.
How to Install Android 2.3.6 Gingerbread (GRK39F) On Nexus One
Download Android 2.3.6 Gingerbread (GRK39F) and rename downloaded file to update.zip
Attach your Nexus One to computer via USB cable and transfer update.zip file to your phone’s SD card’s root instead of placing inside any other folder
To enter into recovery, turn off your mobile and hold down the Power + Volume Down buttons
When you find Bootloader select it and select Recovery
Your phone will reboot and a yellow triangle with an exclamation sign will display
Press and release Power + Volume Up buttons until the recovery screen show off
Select Apply sdcard: update.zip and the update process will start
Reboot your phone
Enjoy, your Nexus One is running over Android 2.3.6 Gingerbread (GRK39F).