Upgrading my HTC G1 to SDK 2.2 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.
Have you tried rooting your G1 and putting something like Cyanogenmod on your phone?  CM6 is currently in Release Candidate status and supports 2.2.  However, you won't get all the features of 2.1+ because the G1 simply cannot do some of them (i.e. LiveWallpapers).