I am NOT quite thinking now... just come back from work. Kind of understand your question, I routinely cloned my SD boot from N800 and stick it into N810 and has NO problem. I have done it more than 20 times. Or, if you mean to copy SD boot from N800 and reverse clone into N810 interanl flash, that is a little bit tricky.

If making a clone SD from N800 to boot for N810 is what you want, it is really not too difficult. You can either use the console tools, or as I prefer, use the one button back up, http://talk.maemo.org/showthread.php?t=29135 thread #6. The idea of the one button back up is, once you did it once, you can keep back up any time you want, and it is only one button. To backup, make clones, SD copies for your royal followers, is just one button away.......................does this sound like some advertisement?

bun