dd if=/dev/mtd/1 of=/tmp/firmware.trx
Now all thats needed to do is SCP the firmware backup to your computer for safe keeping.
So now lets imagine you've done something silly like rm -r -f /jffs/* and now your routers now doing what u like... or maybe you've changed config settings all over the place so much so that u just want to go back to when it worked. Well fear now more, since we've backed up, one simply command and about 3 minutes and we'll be back to normal.
To restore all you need to do is enter the following into an ssh session:
mtd -r write firmware.trx linux
So there you go, all those lost nights sitting up awake scared of router mishaps, now you're safe.. *sigh* night night :p