After finally getting CyanogenMod 6.0 RC1 to work on my phone (Hurray for Froyo!), I felt like getting a little dangerous and checking out the ROM Manager, and updating my Recovery partition from the very old JesusFreke version. The problem was that running the "Install ClockworkMod Recovery" tool reported sucesss, but when restarting my phone, neither the recovery partition, nor normal boot worked.

I have learned a lot about my phone while fixing this, and below are the steps to resolve this and get a working Recovery partition. I believe the entire issue is caused by a lack of memory on the G1 when running CM6.0 that results in the Recovery partition install failing, while still reporting success. I'm going to assume you have the Danger SPL because this is required to get G1 working at all with CM 6.0.

Steps to fix

1. Pull the battery or start your phone from the "off" position
2. Let your phone charge for around 20 minutes (or ensure you have at least that much battery power)
3. Hold the back button and press power - The phone should enter "fastboot" mode, which actually comes from your phone's SPL.
4. Press the button associated with "Reset", which is also called "Send' or the "Call button".
5. Reboot your phone - You should now be able to get back into your main CM 6.0 install.
6. Turn off the phone again
7. Hold the back button and press power again - The phone should again enter "fastboot" mode.
8. Plug in a USB cable to your computer
9. Download fastboot from http://developer.htc.com/adp.html
10. Download the Recovery Image you want (For me this was RA-dream-v1.7.0.img, but check the bottom of this forum post to make sure you have the most recent version.
11. Run fastboot flash recovery (On linux this was sudo ./fastboot flash recovery ~/recovery-RA-dream-v1.7.0.img) - This uses your "fastboot" mode phone that has plenty of memory to write the new recovery image properly.
12. Reboot (sudo ./fastboot reboot works in linux)
13. Reboot or power on while holding "Home", and you should boot into your recovery partition.
14. Everything should work at this point, your SPL which you didn't touch, your recovery partition which you overwrote, and your main partition which you reset into a working state. Congratulations!

Still having issues?

Leave a comment and hopefully I or someone else can help you.