Cloning Hard Drives
dd if=/dev/SOURCE of=/dev/DESTINATION bs=1M
I've found in my experience 1M tends to be a solid "bs" number; lower than that and the copy rate is slower, higher than that doesn't give much performance gain (if any). The SOURCE should be the hard disk that has the image you want to keep and clone, the DESTINATION should be the hard disk that is to be cloned and receive the image on the SOURCE.
This will copy, bit-for-bit, everything on one hard disk to another. Useful for copying over complex workstation/server configurations on machines with the same hardware.
Mounting a JFFS2 filesystem in Linux
This is described on this mailing list, but here's the short of it in case that page ever dies:
If /dev/mtdblock0 doesn't exist, do the following
mknod /dev/mtdblock0 b 31 0
Then do the following. The kernel modules can be enabled under Device Drivers->MTD. Make sure to get them all.
modprobe mtd # get this when enabling MTD
modprobe jffs2 # under Filesystems, Misc
modprobe mtdram # under MTD section
modprobe mtdchar # under MTD section
modprobe mtdblock # under MTD section
dd if=your.jffs2 of=/dev/mtd0
mount -t jffs2 /dev/mtdblock0 /your-mount-point
