If you do not want to lose OS2006 in flash you can backup it first via mkfs.jffs2 (when booted from mmc) as mentioned here http://www.internettablettalk.com/fo...8&postcount=31 , then reflash with OS2007 rootfs, clone it to mmc (if you have some spare partition on mmc) and reflash again with previous OS2006 backup. Sadly extracting jffs2 image directly to mmc is not that easy.