I am pretty sure, you will have to repair multiboot, multiboot-kernel options.
For multiboot you have to have an image for each of the kernels you have installed / want to boot. You better search for the multiboot thread to avoid further issues. You could search for multiboot from the X-Terminal pretty quicklyonce Maemo is up and running.

If you happen to have kernel-power running when things failed, you will not be able to boot via PC command as is in the wiki