ah, now I have to show my ignorance! I can chroot /mnt/initfs but dont know how to try to mount mmcblk0p2 while there.
chroot /mnt/initfs insmod /lib/modules/2.6.21-omap1/mbcache.ko insmod /lib/modules/2.6.21-omap1/ext2.ko mount -t ext2 /dev/mmcblk0p2 /mnt/new_root ls -l /mnt/new_root umount /mnt/new_root exit