Good news for all US based T-Mobile G1 users as the Android OS 1.5 update is now available for download. This means that G1 users can now enjoy a tweaked UI, video recording, voice search, an on-screen keyboard, an extended library of widgets, stereo Bluetooth, better battery life, faster speed and many more new features on their Android devices.

The Cupcake update can be downloaded from Google's Android Code website and installed manually. The OTA version, which allows users to automatically update their Android devices has been delayed due to some security reasons and will be available soon. Here's how you can manually install the Cupcake patch:

Note: Install this at your own Risk.

1. Download the signed-kila-ota-148830.de6a94ca.zip file from Google Android Code website
2. Rename the signed-kila-ota-148830.de6a94ca.zip file to update.zip
3. Transfer the update.zip file from your PC to ROOT of the G1 or G1's MicroSD card
4. Power off your G1
5. Press your G1's Home and Power buttons
6. Press ALT+L keys on your G1 keyboard to bring up the command terminal
7. Press ALT+S keys to install the patch
8. After the patch has been installed, press Home and Back buttons for manual reboot

Source: Mobile Crunch