Originally Posted by juiceme

To just remove ubiboot without wiping the device is very easy.
All you need to do is flash a regular kernel to the device to replace the ubiboot kernel and you are done

If you have just Nitdroid and no Nemo on your device it is easy to reclaim the space used by Nitdroid after you boot to normal Harmattan; just remove the directory containing the Android subsytem and that's it.
If you hsve also Nemo/Sailfish/Ubunti/Firefox/whatever it is a bit more difficult since that means your device has been repartitioned accordingly.
That's doable too, but requires a bit more expertise.