On my Nokia 770, I use a 128mb rs-mmc card formatted with ext3 to hold the development rootfs.
./flasher --set-root-device mmcAnd to resume normal operation:
./flasher --set-root-device flashHowever flasher needs a PC at hand- cal-tool to the rescue!
For development (on mmc):
chroot /mnt/initfs cal-tool -R mmc
For release (on flash):
sudo gainrootN.B. This command requires xterm and root permissions on both your release and development (so you can switch back) images.
chroot /mnt/initfs cal-tool -R flash