In the end, I went along with this. So far so good.
Ubiboot, Maemo Leste installed. :-)

I was asking this because I have already done this before but after a while, my phone suddenly, did not want to start. I had to reflash it with the "erase-user-data" option to get it working again.
I think now that it was not because of the partitioning, but something else. Time will tell! :-)