The nand is: the lflash (the firmware), keys and the IPL i think.I advice to make a backup of your nand as soon as possible, it will save your life, sooner or later.
you don't need another memory stick.Use Cory's tool.
Or Pandora's battery or Despertar del cementerio.But i heard that despertar del cementerio has some issues fixing bad blocks, so i advice to go with Cory's nandtool.(click here)
which nandtool do i have to choose? and how do you use it?
also how can you mixed up your nand? maybe i dont need it if i just dont use something about it.
nandTool 0.3 beta
What do you mean by mixed up?
Well, if you're more interested in themes just backup the flash0 normally.
well i use themes too. but i use the ptf files.