Ok this is all data from XDA-Developers:
Google Download:
https://android.clients.google.com/u...-RC19+RC28.zip
**This download might need to be refreshed once or twice before it works. If you get 503 server error, try again, if it doesn't work after a while use the links below.
Rapidshare Download 1:
http://rapidshare.com/files/15924331...-RC19_RC28.zip
Rapidshare Download 2:
http://rapidshare.com/files/15924473..._RC28.zip.html
Rapidshare Download 3:
http://rapidshare.com/files/159411433/update.zip.html
Android-DLS.com:
http://android-dls.com/forum/index.p...rb_v=viewtopic (Must be registered)
Steps to upgrade:
1: Download the file and rename/save it as update.zip (some users found just plain update works best (no .zip))
2: Place the file on your mini SD card and insert it into your G1 (card formatting requirements still unknown, so if fat does not work, try fat32 and vice versa)
3: With the phone off Hold down the "Home" and press the power button (end call) to turn the phone on (while still holding the home button)
3: Wait for the following screen
4: open your keyboard and press Alt+L
5: When you see yellow text, pless Alt+S
6: When it says "Installation Complete" you can press "Home" + "Back" to reboot.
7: Wait for your phone to completely reboot and allow it to finish writing your radio rom during reboot, it may reboot multiple times.
8: Enjoy
These instructions are paraphrased from other users and are not written by me.
Hope this works for everyone...
[Edit:
Method not endorsed by androidforums.com, perform at your own risk.]