Cheers Airbag888 for bringing this exploit to our attention (and of course everyone else involved in finding the exploit and scripting it)
Works like a charm. I couldn't revert back to the older 2.3.3 Gingerbread after HTC fixed my power button. Suffered the "Main version is older" error downgrading and nothing else worked.
My Nexus is now safely reunited with CyanogenMod and I'm mighty happy
Sent from my Nexus One using XDA App
Samsung Note 2 - Dr Ketan's ROM
Nexus One - CM 7.1 final (still using as a backup phone!)