I managed to flash the kernel, but this was not the problem.

I tried to install NITdroid, but did it wrong (obviously). I now get the multiboot menu when I boot the phone, but with just one option: 1. Nitdroid. And the nitdroid version doesnt work/boot. So basicly i'm stuck here.

Is there a way do delete the multiboot from the n900? As I said I flashed the kernel, but this had no effect.

I appreciate it.