I made a little bit progress, took the Meego RAW Image and the Latest WebOS Doctor image ( includes a rootfs image and uImage ).

Wrote the MeeGo image to a SD card and exchanged the rootfs files,
( but not the uImage on the fat partition, that wouldn't even start up ).

It boots a little bit but at a certain point the screen starts to falsh and halts.

Downside is without debugging tools I can't do very much from here. When the Pre3 comes out I will buy that, but in the meantime I wanted to have a usable Software on my n900.