I am trying to upgrade my HTC G1 to OS 2.2 (I have a developer device bought way back when it was released)

I have been trying the steps provided here - http://code.google.com/p/android-roms/wiki/SPL but for some reason the phone won't boot up after following all the steps. I have tried twice and restored my device to 1.5. But would really like to upgrade to 2.2

Any ideas please?

Thanks.