To manually install Android 2.2 on the Nexus One, perform the following steps:
- Download the official Android 2.2 firmware for the Nexus One.
- Copy the file to your microSD card and name it update.zip (newb warning: not update.zip.zip)
- Power off your phone.
- Hold down the VOLUME DOWN button and power it back on.
- The phone will now search for files like PB00IMG.zip, etc. This is normal. Scroll down to recovery and press the POWER button.
- When you see the “/!\” symbol, press the POWER button and the Volume Up button at the same time. You should be presented with a menu and one of the options should be “Apply sdcard:update.zip”.
- Use the trackball to navigate to “apply sdcard:update.zip” and select it.
- When you see “Install from sdcard complete”, select “reboot system now”.
Enjoy and once you’ve had a chance to play for awhile let us know what you think.The resources:
- Upgrade from Android 2.1 (ERE27) to FRF50.
- Upgrade from FRF50 to FRF83.
- Upgrade from FRF72 to FRF83.
- Upgrade from ERD79 to ERE27. (~16MB),
- Update for ERE27. (~65MB)
(Referred from: AndroidAndMe, Links from the Net)