I have installed N11 last week. Today i wanted to try ICS, so I installed it but I couldn't get passed the "touch the android" screen, no matter what I tried, it kept telling me that the the startup wizard crashed. Not a huge problem, I didn't care a lot. So I removed ICS.
Now, I couldn't boot into power kernel49, the entry was still in multiboot, but it created a reboot loop.
I booted into the default kernel and installed N12. To do that, I had to reinstall the nitdroid installer (v9 beta3) for some reason, although I didn't uninstall it.
Now the problem is that there only the nitdroid entry in multiboot. There's no entry for default kernel, or power 49! and even if I restart with the keyboard closed, multiboot menu is shown.
So, any opinions, any help?

edit: when I press 0 to load default kernel, it gives a guru meditation error.
edit 2: I just reflashed and everything back to normal. So consider this a warning about things that could go wrong.