Okay, here's the sad story so far: I have a (previously) unmodded G1, with normal T-Mobile software. Yesterday morning around 5AM I get the little notice that I can upgrade to Cupcake. Unfortunately, it's 5 in the morning, I couldn't sleep, and I wasn't thinking all that straight... so I decided to root my phone and upgrade it to 1.5 instead. So I downgraded to RC29, got myself root access, and installed the latest Jesus Freke build. Now the fun starts. As soon as the phone boots into the JF build I get constant android.process.acore force close errors. And I do mean constant, I force close, and it pops up again, force close, pop up again ad infinatum. I reflashed a few more times, varying the order of installing the radio update and misc. stuff like that, but still no luck. So I decide to go back to the T-Mobile build without root access. I mean, I lived without it before, and not having root is better than not having a functioning phone, right? So I download the official cupcake update from google's dev site and install that. Woohoo, no more force closing, it looks like everything works! Orrrrr not. I can't get into Settings now. I've tried to open Settings from the home menu, from a shortcut on the desktop, and through the menu button. Every time I try to do so, it will open up a black screen (like it's starting to load the settings menu), stay there for anywhere between 1-4 seconds, then go back to the main desktop screen. Everything else on the phone works, Market, Camcorder, soft keyboard, everything. Most apps I've downloaded also seem to work. However, when I installed the Toggle Settings app and tried to toggle the GPS, it popped into the settings menu with a black screen with the Security and Location text at the top, and then promptly went back to the app without changing the GPS. Then I flashed it back to RC29, manually upgraded to RC30, and left it overnight. Next morning the OTA update to cupcake was available, so I installed that. Unfortunately, the problem with the settings menu is still there. I've tried everything I can think of at this point and the almighty Google doesn't seem to have any answers, anyone else able to give me some help? It would be much appreciated.