This weekend I updated my phone from CyanogenMod 5.0.8 to CyanogenMod 6.0 RC1. This is a great improvement that has improved the stability, speed, and visual appeal of my phone. Despite some ongoing issues with the market, my phone is in the best state it has ever been in.
Since things were going so well, I decided to try using the ROM Manager included in the release. The ROM Manager has a built in tool to install the ClockworkMod Recovery image. A couple of taps later and my device reported that the ROM Manager was installed. I attempted to reboot my phone and was left with a persistant "G1" message that would never go away. This occurred regardless of whether I attempted to boot normally or into Recovery Mode. Thinking my phone was permanently bricked scared me a lot.
The "fix" (although I still have no Recovery Image) was to hold the camera button when booting the phone, and then tell what I believe was Danger SPL to reset my phone. This was a very scary menu option, but thinking my phone was bricked meant I had nothing to lose. After pressing the reset button and restarting my phone, it booted fine back into CM 6.0 RC1, with all of my data, apps, and settings still in place.
In the end, I am running Froyo (Android 2.2) on my G1, and I'm pretty happy with it. The market crashes and I can't install some apps that started downloaded but never finished. I have no recovery image, my phone is still slower than I would like it to be (Not CyanogenMod or Froyo's fault), and voice text entry doesn't work. On the other hand the Gallery application now has 3D presentation of my photos and videos (including those stored on my device, but not taken from my device); it is reasonably fast too.
I'm waiting to see if any of these items are improved or fixed in the next release, as always.