There are plenty of threads here explaining how to clone the OS from internal memory to the MMC/SD-card.

What I want to do is a little different: I want to leave the running OS 2006 on my 770 untouched, use the boot-menu (already have this *g*) and get a working image of OS2007HE on my MMC card. (I have a crad reader on my desktop linux PC, so it's really easy for me to do all the steps there.)

Unfortunately, I don't get very far. I had some more problems in the beginning (thread here) and benson helped me a lot during these ealry steps, but I'm still stuck on how to get a working setup on the MMC-partition:

I can easily extract the contents of both rootfs.jffs2 and initfs.jffs2 on my desktop PC, but how do I combine them to get a running system?

First I thought rootfs.jffs2 would be enough, but it isnt. Then I added the contents of initfs.jffs2 to /mnt/initfs in the root fs, but it still doesnt boot.

Anybody done this before? What am I missing?

And: Is there any place I can go for debugging information? I get the boot menu, select the entry, and after a few seconds I'm at the boot menu again... Not very helpful. Is there a way to read what happened afterwards? Like missing modules, wrong paths etc etc...?

It would be so cool to just copy whatever version of ITOS to MMC without going through the "flash-copy to MMC-reflash original"-hassle. I'd even consider OS2005 just for the fun of it - I can't remeber what it looked like at all.